Southern region South Coast covers a large area , spanning all three sections. I believe that O2's were all on the I.O.W. by nationalisation, and the USA tanks were confined to Southampton Docks until the preservation era. As a rule of thumb, the Western section was the preserve of M7's, the central section was the preserve of M7's, E4's, and H class tanks, while the Eastern section was almost exclusively serves by the h class. The BR 4MT 's were, of course, pretty universal. The H class is available RTR from one of the smaller suppliers ( sorry, can't remember which one ), while, if the South Eastern Finecast is too daunting, there was an article some time ago in Modelling Railways Illustrated which described the conversion of a 14XX into an H.

Along the coastal routes, steam was confined to goods working ( apart from The Lancing Belle ). Inland, of course, on non-electrified branches, steam was used exclusively..

For tender engines, the c class was on the Eastern and Central sections, while both  the N and Q1  reigned supreme on the Western section. Sadly, we are unlikely to see a C2X or 700 in RTR.

I hope this helps

Thank you, yes thats brilliant. Basically its based its a Southern terminus based in Sussex so something like the E4 would probably be most suitable but i suppose i could always pass the USA tanks off as doing trials in the harbour.  

Thanks for your comments