[Mr Tom Morrow]

I think we all mixed our own. Powdered lime and water. Almost certainly never wore a mask either as the dust rose when tipping it in the galvanized bucket

I would opt for 10 lites of basic masonry paint from Screwfix for £24.99. Good stuff.

screwfix/p/no-nonsen...te-10ltr/13039

Currently not in stock but will be soon.

This stuff is available but a few £ more.

screwfix/p/sandtex-f...te-10ltr/21138

The traditional powder you would need is very much like Tarmac Limelite, comes in a bag. Dangerous!