Id like to do a model of 47004 "Old Oak Common Traction & Rolling Stock Depot" after remembering I saw it at the 2000 Old Oak Common open day (was it really 12 years ago  ) and wondering where to start!!!
I could buy a BR Green 47 that already is painted and replace the headcodes with 0F70 and add headlights at either end or buy one of the newer Farish 47s and respray it green.........

You could get one of the new ones in green and just renumber and add Ratio headlamps/change the headcode.
Just need to make sure you get one with the right type of radiators, need to be the 2 panel Serck type.