Tomix container wagon bashing?

[mickster04]

I was wondering if anyone had any experience using Tomix container wagons as a basis for modification to be used in a british layout, and if so, which ones.

how severe were modifications?
I was hoping to source a few cheaply but there is a bit of choice involved... I don't need extreme exactness otherwise I would go for actual british ones, but something that wouldn't look outrageous would be good

[EDIT]I recently realised that japan models in 1:150 has anyone got any experience with this being a noticeable difference in scale compared to british rail stock?[/EDIT]