You can insist all you like, if the GP won't prescribe them then you have to get them elsewhere. There is no right to test strips, especially if you are diet only as the OP is.
My Life - Pura sell their strips direct for £14 per 50 delivered via their UK agents gbhealthcare.com if that is any help. You would need to declare diabetes though to get this VAT free price.
I buy mine from Amazon - Pharmacy Place reseller. About £20 for 50 (Aviva) and they are dead fast delivery - I always leave it very late but they get them to me within 2 days normally - even at Christmas .
I started off buying my own on Ebay, a lot cheaper than buying in the chemist. I asked my DSN and she said it was okay for me to get them on repeat prescription :mrgreen: I don't know how many I am allowed. Some doctors have restrictions on how many pots you are allowed a year.
What meter are you using? Have a look on the manufacturers website, or give them a ring.