This was brought up during the time of the last club release, they won't do it due to the flush cab sides and additional cooling panel, even though I'm sure they would sell really well in Colas, not so much in the Green IMHO though, I thought it was a bit drab, although it is most unusual..
A pair of GBRf 20's in the orange livery would be different, one dummy, one powered, there are lots of unusual GB 66's to pick from, the MSC boat one, the rainbow one, one of the tube map one's, or how about 66747, 8 or 9 or 750 in the grey or blue euro liveries would be fine.. .
My only negative thought is will they sell though..