norwich & Peterborough approved solicitor

Hello,
I have had an offer accepted on a house.

The estate agent recommended 2 solicitors to act on my behalf, on account that a local solicitor would be ideal because they know the local area etc.

I spoke to a solicitor recommended by my mum and he suggested using a solicitor that is approved by the mortgage lender.

I asked N&P if the 2 suggested solicitors are approved, which they are not. N&P got back to me pointing out where they can fill out the appropriate forms to become approved.

Do I
A: save myself the bother and use one of N&P's solicitors, which no doubt won't be local to the area I'm buying (Central London)

B: use the local solicitor and accept there may be delays etc as they go through the approval process.

Any advise, would be massively appreciated.

thanks Metso