The CAA response has now been published. CAP 1920, 18 June.
https://publicapps.caa.co.uk/docs/33...g_Response.pdf
It suggests that only new types will be covered by the 600kg extension.
There are lots of aircraft flying as microlights which have been internationally certified at higher weights.
Can we assume that we could simply re-certify these types, and thus create a "new type"?
It would seem bizarre to have two identical aircraft flown by the same pilot on the same licence, and one of them allowed to carry 150kg more.