Recommend a decent gas blow torch, I've saw the name Rothenberg and Mapp but expensive, I expected to get one (maybe not these names) for about 20 odd quid. I also read the Mapp gas is better/hotter than butane and loosening rusty bolts ect.....advice and opinions please

Rothenberg is the best by far but as you said you will pay for it. Not sure about the £20 mark I can't see any of them being upto much. B&Q might do one around that price. And as for the gas I only ever use butane or propane. Depends on what size pipe I use but propane is the one I use more.