Much as I'd kill for a few Mk3 push-pull sets, I suspect that Mk4's might be a better bet, as they've been on the go a while, and probably have a good few years left in them.
Same here, a bit freight-heavy, and hungry for IR / IE passenger stock.
Yeah, and in ten or twenty years time, what is currently on the rails may actually be legacy stock, the grey 071's being the stuff of legend that people can barely remember.
I guess if you were to run a shorter train, not prototypical length, that would solve that problem! Because of the length of the coaches, less units are needed to build up a nice long train to fit within ones desired space.