Money exchange

Hi all can anyone tell me where I can get some cash changed up into euros on a Sunday

Try zenia boulevard

There are no money exchange places at Zenia Boulevard. There is one in La Zenia (not the same place) but that doesn't open Sundays.
The Caja Rural bank at Zenia Boulevard is not open on Sundays and they won't do money exchange unless you have an account with them.
I would think the only one open on Sundays is at the airport (either Alicante or Murcia) but a. it's a long way to go and b. you'll get a rip-off rate and is currently around £1 for €1 if you just turn up.
Best bet is use a UK debit card in one of the ATMs (or a credit card but there'll be extra charges for taking cash).

If you need euros go to cash point and get from your own bank account or poss sea front torreveja