Prepaid Postal Stationary used contemporarily in the UK

Hi. Prepaid postal stationery, as in envelopes or items with postage already paid and printed on, is a concept which was once very popular but has now largely died out. This is definitely the case in the UK. I don't mean things like PPI/Account graphics or frankings. I have 2 items to share. The first is still used and has been for many years, a House of Commons envelope. These are available to members of parliament to mainly reply to their constituents' enquiries. My example was interestingly postmarked at Edinburgh Mail Centre, where the constituency is, and not Mount Pleasant or another London area facility. Two-wave postmark often used on non-standard size/type mail. Date 07/03/2025(?) One thing to note is how both items shown here have the Machin image used to represent Queen Elizabeth II. Of course, we have a new monarch, so while the second item is now discontinued, the House of Commons envelopes join a stil...