Check out if your local authority do any kind of cycling scheme.
My local authority do a scheme that provides cut price bikes andaccessories, bikeability training and cut price bike maintenance courses.
I did the bike maintenance course which was a revelation to me and i can now do lits of tweaks and snall jobs on my bike though I do still use the bike shop for some jobs.
+!
We have a centre in Gosport that has a range of second hand parts, often in good nick at a fraction of the price of new