Here is a clue. There is a company in the UK (possibly this one) that has supplied a good number of the APC version to Ukraine. This could be a follow up.
I have found the Video that backs up what I read a few months ago
View: https://www.youtube.com/watch?v=emN3LoJMwrE
These systems are probably mainly surplus and/or ex Afghanistan related vehicles aren't they? Its not the company (Alvis?) whos supplying them is it? Don't they actually come from the UKs already ridiculously small reserves?