I think a few of the chaps above have answered your question
I do have a few TM's, probably more than I need to be honest, and I will be slimming down my collection so selling off my SOPMOD and my 416D when I get my finger out...They will pay for the MP5 so I'll recycle the money I have invested. But going back to TM's they just work out of the box and a stock TM will easily chuck a 0.28g 50-55m with good groupings. And swap out the spring guide and wallop 5-10fps increase! and if you are feeling brave then a TB barrel and a purple prommy hop and you are looking at another 5-10 fps... I do own a Systema PTW too though and that outguns my upgraded TM's marginally I guess...
TM's tend to come into the country by one importer and then they are divided up between the UK retailers according to their stock allocation so I expect all UK retailers will get them at the same time.. But CAMO may have an alternative source so it's anyones guess...