Welcome settlement figure

Hello,
I am very new to this forum today in fact and make pre apology for any ignorance.

Also may I provide apology for the long and verbose post, I do feel that in the first instance information is king and assists in an informed response.

Please bare with me in summery I feel that Welcome finance have charged me far more than they should have for the loan
I am looking for any advice in dealing with what I consider to be an unfair trading practice resulting from a secured loan with a company called Welcome Finance.
Firstly, the loan is fully settled and there are no outstanding amounts.

I am also able to say that I am fully aware if I enter into a legal agreement with a finance company I am obliged to continue to honour such an agreement, regardless of my financial situation, thankfully, this is not a consideration in this matter.

I will firstly lay out as much information as possible
Background;

In October of 2008 I contacted a company being Bluesky Personal Finance, Located at Tinturn House, William Brown Close, Llantrnam Park, Gwmbran, ND44 3AB Blusky being a finance broker.
Bluesky providing me with details of a finance company that was able to provide me with a loan secured against a property that I owned.

I researched the company Welcome Finance, at the time Welcome Finance and its associated companies were correctly licensed and regulated by the Financial Services Authority having registration number 305742.

Specific details of the loan to be provided by Welcome Finance.
Initial request for total credit to be provided £5000.00

Additions to total credit (insurance premium) £981.51
Total amount of advance £5981.51
Period of loan in months 36
Acceptance Fee £235.00
Broker Fee £250.00
APR 31.17%
Rate of interest per annum 23.87%
Total interest charge over loan period £2375.91
The interest rate was very high, however in desperate need to clear outstanding debt as soon as possible, I was then contacted by Welcome Finance in late November of that year, them providing confirmation of my acceptance and them providing me with credit of £6466.51 this comprising of
Cash amount advanced £5000.00
Broker fee £250.00
Acceptance Fee £235.00
One off Insurance Fee £981.51
Total £6466.51
Welcome finance providing a opening balance date on this loan as 12 November 2008.

£245.62 to be taken from my account on or around the 16th of the month for a period of 36 months, the first payment in respect of this matter to be taken 16 December 2008

On Tuesday 16 December 2008 a direct debit payment was made to Welcome Finance for £245.62 as agreed with the terms of my regulated agreement.

I then continued to make regular monthly payments of the same amount between 16 January 2009 and 16 May 2011.
This amounting to 30 payments

In May of 2011 I I contacted Welcome finance and asked them to provide a settlement figure for the loan.

Online inquires; these showed that Welcome Finance were no longer providing financial products and were been investigated there regulator.

In mid May 2011 after making my contractual payment to Welcome on 16 May 2011 I contacted Welcome Finance, by telephone and asked for a figure to clear my loan with them, provide a settlement figure.

I had a rough idea of what I considered to be the amount in any respect I considered that it would not be greater that the total loan if it were to have run its full length another 6 months.
This assumption being based on Welcome Finance initial agreement
Loan amount £6466.51
Interest over term of loan £2375.91
Total amount to pay £8842.92
30 payments of £245.62
Total payments made £7368.60
Total amount owing including all
Capital and interest £1474.32

I spoke to Welcome finance who told me I owed a sum significantly larger than that owing if I were to continue to make regular payments of £245.62 for 6 further months.

Not being able to understand why this should be, I was told that this was interest to settlement, I then asked on more than one occasion to be provided with the calculations that derived these figures.

On each occasion was told this is not possible, as these figures were arrived at by a computer and were not based on simple maths.

I am able to state that I am unable to recall the exact amount to settle I can say that it was in excess of £1700.00.

I told the person at Welcome Finance, I was not able to comment on their figures as I did not have all the facts available.

In short I made numerous attempts to get Welcome finance to justify the figure them being dam right obnoxious.

I eventually told them that I would not continue to pay them until they provided information to substantiate there settlement figure.
Welcom finance wrote to me on a number of occasions after this demanding payment until 30 September 2011, the wrote to me with a default notice served under S87(1) of the Consumer Credit Act 1974.

The sums described in this default notice;
Total amount outstanding £1491.94
Rebate of acceptance fee and charges £0.02
Rebate of insurance £0.00
Collections fees ` £12.72
Default Interest £21.48
Interest to settlement £1855.92
Now this is where I get totally lost.

If I had continued to make the remaining 6 payments of £245.62 as contracted to Welcome finance the total amount that would have to be paid give or take a bit of additional interest on the four missed payments surely would have amounted to simple arithmetic. £245.62 x 6 = £1473.72 plus the adjustments in the default notice £1507.92.

This amounting to total payments over the period of the loan of £8842.32 + a bit of default interest and such like. This reflecting the original agreement.

Any way I paid them £1058.00 not wishing to be in breach of the notice.

This leaving making my total payment to the loan £8426.60.
I assumed as the total amount of the agreement was £8842.92 + the add on’s of
Collections fees ` £12.72
Default Interest £21.48
Making a total of £8877.12
Less payments of £8426.60
Would leave a total sum to be paid of £8877.12 - £8426.60 = £450.52.

When I then asked Welcome for the final settlement in November they provided the following
Total amount outstanding £484.32
Rebate of Acceptance fees and charges £00.00
Rebate of insurances £00.00
Collection fees £22.90
Default interst £2.32
Interest to settlement £280.94
Settlement figure to pay £790.48

Needless to say I raised an objection to this and was told by Welcome tough, sick of the company I paid.

Now I may have missed something or have I been made to pay £9217.08

After removing of misc fees and interest £91576.66

This some being £314.73 that the total contractual amount had the loan continued for 36 months.

Please help if you can as I feel that I must be really stupid and mist something