I think initially, the intent was that Type 31 would be a stripped out Type 26 (No Mission Bay, no towed array & a few other bits n bobs, but effectively using the same hull form, if a little shorter.
After a while that changed & it looked like it was going to be a design based on the Oman OPV's
Khareef Class Corvettes - Naval Technology
But of late, I can't say that I've heard anything.
With x6 T45's, x2 CVF, x2 Albion class LPD(R)'s & the use of x3 LSD(A)'s, plus the x2 oilers, the current x3 Rivers & the replacement x5 in production, the RN will have to seriously look at how they intend to progress.
Like many nations our mix of High / Low order ships, their age & the ability to actually man & run them will be a key factor.
With the announcement of the 1st batch of x3 Type 26's being less than a week old, it's fair to say that by the time we get to 2023 / 2025, they will have damned good idea of what they want.
Personally, I think that UK PLC should shy away from the farce of attempting to build ships as units, in different parts of the country, using different suppliers, then shipping them to a central site for assembly & only then trying to fix all the issues while failing to deliver a product on time, to a budget. (t
he issues with both Type 45 & CVF should be pretty much the examples to prove that it DOESN'T work !)
Anyway, here's hoping it's MORE Type 26's !
SA