Reddit mentions of Parchment Paper Natural A4 90gsm

I used https://freedeedpoll.org.uk, just to add to that chorus.

A good hack is to print it off on "parchment paper". (Like https://www.amazon.co.uk/gp/product/B00IJA5FR6.) This isn't necessary, but it does make it look more official - and that is the thing.

Then, having done that, get a (provisional at least) driving license in that name, which gives you some photo ID. It won't have the hidden gender marker correct, but that's sortable later and is non-obvious. Then you can use that plus the deed poll (plus any old ID) to change name in various places. If you can project confidence, you are less likely to have anyone question the name change/ask for something "more official", but you should be fine in any case.

The only thing that required any more faff was my passport - for that I also needed a letter from the doctor to change gender marker. This wasn't too hard to get either though - did it via GP once I was on hormones from the GIC.