Before I retired a year or so ago, I was the UK agent for a Spanish made
product called 'Supertape'

It's masking paper on the roll (150mm, 300mm, 450mm widths), with a 25mm low
tack adhesive coatting along one edge.

It's a cracking aid for cutting in, and much cheaper than the US made
alternative, 'Easymask'

Sadly, the DIY sheds never took up the product, but I can pass on the details
of the main uk distributor (no, I'm no longer on commission!)