Probate advice needed

Jskel

I'm hoping someone out there can advise me, or at least point me in the right direction.  My sister died last year, having made out 2 wills, a few months apart, whilst her mental health was a bit questionable, although there was no formal diagnosis of dementia at the time.  The content of both wills is the same, the only change is to the executors, making my cousin and me joint executors on the second will.  However, the second will was not correctly witnessed.  After a lengthy battle with my cousin over the estate, (I believed the first will was made under duress), she has settled for a payment, and I have a Deed of Variation, Settlement Agreement and Power of Attorney document with which to obtain probate on the first will.  My solicitor is telling me we need to get affidavits from the witnesses to the second will with which to rebutt it, in order to go to probate.  They are talking high court etc., but the probate office have told me this morning that they are only interested in the will that has the agreement.  Solicitor is sticking to his guns, and now I have found out that the original of the will that has the agreement on it has gone missing. 
I feel like dumping the solicitors and doing it myself, but it looks like I'm in a bit of a mine field.

TBagpuss

In what way was the second will not witnessed correctly? 
If its obvious (e.g. not signed, or only one witness) then it's invalid and you don't need it.
If it was signed by teo witnesses but they didn't see the testator sign, or they witnessed it at different time, then it would be prudent to get statements to that effect from them even if you don't go to court.

However, the deed of variation may be key here - 

Jskel

Thank you!  The witnesses did not see her sign the will.  Deed of variation is drawn up to vary the May will to give the settlement to the cousin, full and final.

Jskel

And just to make things worse, the solicitors no longer have the original of the will that I need for the probate application