Northwesthardware site
My lock bust on a 10yr old UPVC window when I came to check it found I need new handles to.
I am lucky they are just around the corner from me, so called them up and they advised me to remove the locking strip (Espag) and bring it in as if they didnt stock it they would be able to order it.
Thinking yeah yeah heard this before so did as asked and took the strip, the staff were awesome, friendly non of the oh so your joe public as they had a carpark full of trade vans coming and going.
They identified what my espag was and ordered it 3 days later called me and for £12 + vat complete new strip, also new set of handles £12 + vat.
other sites wanted £30 and were unsure if they could get one.
I would definately say the service I got from them was excellent, they also stock loads of locks as whilst I was there a few locksmiths were in and out.
keep them in mind if you need locks or UPVC supplies.