No british CL, but I know a few people who have snakes in Sommerset, just ask on a local FB group if anyone wants them.
Id just feed them to your snake, she'll probably take them anyway, and it would do until you can get anything better
Also if you're looking for frozen food suppliers in England... TSM pet supplies and Kiezebrink all sell high quality food and they are quite cheap also!
Kiezebrink you have to buy in bulk (eg, you can only buy a pack of 10 or 25 LRW, no in between) but TSM you can get all the food in the exact quantity you want, and is a ickle bit cheaper than Kiezebrink.