There's some interesting post election anaylsis that picks up on this (in Wales at least). There's a view [0][1] that while results are bad for Plaid, they're getting a lot of what they want, and shifting the window on the most important issue (independence). In addition to UBI, it's interesting that Welsh Labour have started the push for "home rule" [2], something that is likely to win them a lot more votes from traditional Plaid Cymru supporters.
Yep, Welsh Labour clearly learnt the lessons of Holyrood and are determined to avoid a Scottish scenario playing out in Wales. They are also helped by the fact that Labour is unlikely to get any sort of realistic shot at a Westminster majority anytime soon, so the periphery is quite free to set their own agenda. English Labour can quietly support a breakup of the Union that will then try to tie around the necks of Tories and SNP, they have little to lose now.