Buy some 18mm ply and cut some squares / rounds to sit under the cabinet feet. Drill 3mm recesses in each with a spade bit. Give a good coat of pu varnish.
Immovable 15mm packs.
The best bit it Dad was a BG pensioner, one of their own you might say. They took the header tank out and replaced with a small pressure vessel to make a sealed system.
I bought a Wickes branded Earlex WD1000 over 30 years ago. Still my goto shop / car vac. It's had one full strip down and clean. The thing just goes on and on. I've two identical combi filters I alternate between. Just hose them off and let dry. Chippy mate has the same one and loves it the same.
Wish I'd bought another when TLC were selling them off.
They sometimes come up on Gumtree etc.
I have run some 15mm Pex/PB inside 25mm galv electrical conduit. This was in the corner of a wall but that was more for mechanical protection against someone deciding it would be a good spot for a shelf bracket. It'd be a bit moot if someone decides to use a Bosch multi construction bit!