Or simply waited until a full fat franchise was let. It does seem rather profligate to rebrand for a period of just 54 months. Refurbishments could have been done in existing colours. The toxic word 'First' could have been quietly dropped from the FGW▸ brand.
I thought this got thoroughly aired before, by reference to the franchise agreement. However, I can't find it now. I would have had a futile attempt to find it using the so-called "search" function, but as SQL is currently very unwell I can't do that either.
Anyway, it's in Schedule 14.2 - which I'll quote in its entirety if you like. But the key bit is at the beginning, where it says:
2.2 Subject to any applicable obligations or restrictions on the Franchisee (including the terms of the Rolling Stock Leases), the Franchisee may apply registered or unregistered trademarks (including company names, livery and other distinctive get-up) to any assets owned or used by it in the operation and provision of the Franchise Services.
I wonder how proud Eversheds are of "distinctive get-up" as legal terminology - but it does appear to cover a colour associated with the operator as a company, not with this railway.
The text goes on to say that the operator must not hand over assets with any of this branding that the successor cannot use, or else it must pay for "covering such Marks or otherwise removing all indications of or reference to the Marks in a manner reasonably acceptable to the Secretary of State." This isn't just about trains, either:
(d) The amount to be paid to a Successor Operator under paragraph 2.2(c) may include the reasonable cost of:
(i) removing or covering Marks from the exterior of any rolling stock vehicle;
(ii) removing or covering interior indications of the Marks including upholstery and carpets;
(iii) replacing or covering all station or other signs including bill boards; and
(iv) otherwise ensuring that such removal, covering or replacement is effected with all reasonable care and in such manner that the relevant assets may reasonably continue to be used by a Successor Operator in the provision of the Franchise Services.
I guess that could even extend to the overall colour scheme of the stations too, not just signage, if that was too "corporate".
I can see several grey areas here - such as what about such "marks" applied before this franchise (I have not looked at their first one), or applied now but in the same colours as before, or almost the same colour but a bit darker. As in everything else,
DfT» have set themselves up as arbiter in any disputes between operators, so presumably they would have been consulted as to how they were minded to decide such matters. Of course a lot of the trains will be new, so unless they are left in Hitachi White some colour has to be chosen.