There is a place between Neptune breakers and the one on the corner which does very cheap welding. You have to go into the yard, and it's at the bottom (you will see someone welding in there). I had some welding done and it was 40 quid.
http://maps.google.co.uk/maps?f=d&hl=en&geocode=&saddr=53.399379,-3.032393&daddr=Corporation+Rd,+Birkenhead,+Wirral+CH41,+UK&sll=53.399368,-3.032227&sspn=0.003026,0.006545&ie=UTF8&ll=53.398748,-3.031808&spn=0.003026,0.006545&t=h&z=18