Yeah,I don't see the reason for the common user livery on 231 and 233 but I do really like it. The locos just need the above mentioned additions to be fully Enterprise ready. The livery is basically the Enterprise livery without the swirls almost like 8209 when it went around for a few months in the half finished livery.
No reason they could have put them in Mk4 livery and used the logos like the 071s have, no colour at all.
I find it odd what they did to the common Enterprise fleet livery wise. 206-209 stayed as is, Enterprise to Enterprise. 230 is basically a write off/full rebuild required. 227 and 228 went from Mk4 livery to Enterprise. 231 went Mk4 to CUL and 233 went from Enterprise to CUL.
None of the Enterprise locos have any branding or logos applied to them or either do the CUL locos. Would almost have made as much sense painting 231 and 233 in the 071 livery.