Found this on the mig welding forum
will keep you updated.............
I've found a supplier that does an argon/co2 mix in a range of sizes with no rental & no deposit..!

I've just got what they call a 10 ltr bottle from them for £26+vat delivered. When connected to my reg, it shows 200bar/3000psi to give an idea of fill.

They do the following sizes:

10 ltr - £26+vat
20 ltr - £35+vat
50 ltr - £50+vat

Their details are:
Keygas Wales
Hafod Rd
Hafod Ind Est
Wrexham
LL14 2AT

Tel. 01978 840982 or 07720 404433

[Edited on 16/1/08 by mad-butcher]

Nice one! BOC & Air Products prices for the DIY user are outrageous.

Brilliant! Well done that man.