I think developments like this are great, and I'd love to see one of these locos in its new livery. Having been slightly involved in diesel preservation since the late 1970s, I remember when preservation groups were treated with some disdain by many on the mainline railway (though not all). Since those days, the work done by e.g. the Deltic, AC, and cl50 groups has blurred the distinction and brought classic traction classes back to the main line where they're seen at their best. Anything like this, that allows that to continue is worthwhile for me. FWIW, I thought the original cl50 rail blue livery made them look rather boring, later liveries were much better as is the intended GBRF.
As for renaming locos to portray other members of the class, it's not a new phenomenon, remember the Big 4 were quite capable of doing it with steam locos, often for publicity purposes, and some kept the "wrong" identity throughout the rest of their careers. (That's apart from the swapping of parts during overhauls, meaning that by the end of their lives many steam locos included lots of parts which had started life on other members of the class. There's little ideological purity in these matters.)
Edit: Will it go light engine to Paddington or wherever is starts and it mentions a test run? Will that be early in the morning on during the day?
