Interest only mortgage vs Mortgage reserve facility (Woolwich)

barnishroader

Hi,

I have a mortgage with Woolwich.
With this came a linked current account with a mortgage reserve facility, essentially an overdraft.
I rang to ask could i move to interest only mortgage for a few months as my wife is on maternity pay and i have had a pay cut so the next few months will be tough.

They advised that it would be better to use the overdraft facility to pay my mortgage as a repayment rather than changing as paying off interest only would have an adverse affect on my credit score.
The reserve facility charges 4.99%/month which they said would only be about £8/month.

Is this true about the interest only affecting my credit score?
I would have preferred to do that as the overdraft facility is only going to give me more debt but if it is going to be detrimental then should i just run with the overdraft.
Thankfully i had put a bit of money in that account so am in credit and had been overpaying my mortgage so i can use them the first month!