last time i baught ipa was in maplins. ??11 for a lt which will probably last me a couple of years! its different from meths, to be honest i wont use anything else now as it does such a good job.
Fibre glass pencil, try Lord and Butler? or e-bay
http://cgi.ebay.co.uk/PCB-Glass-Fibre-Abrasive-Pencil-new-Unused_W0QQitemZ360219863848QQcmdZViewItemQQptZUK_Hand_Tools_Equipment?hash=item53dec6eb28
I live in Skewen and have the Swansea - London line at the bottom of the Garden, though i am a member of Barry + Penarth MRC