Like most I' wa struggling to find a cost effective supplier for my TIG Argon and MIG CO2 mix, found out on the MIG Welding Forum of a place near me in Dunsable called Weld-Air. He does a 9.4L cylinder for £105 which includes 3year bottle rental, deposit and a full cylinder. Re-fills are £25 and he delivers locally, open Saturdays etc. Good soloution for me, thought others might be interested. No expensive monthly rental, no environmental charges or collection charges like BOC etc.
He also did me a Seally MIG 150A for £225, used it today and it's great, proper pentration on 5mm plate, set up for big bottles, nice wire feed, on wheels, compact unit, decent torch (not euro), with regulator, 13A plug, a reel o wire, spare tips etc.