Mine worked just fine from a bucket. Used water surprisingly slowly, too.

Eh? So are you saying that they suck water - they don't require any
pressure [at the input end]?

That is exactly what I'm saying.

BTW my last pressure washer (29 quid at B&Q 18 months ago) packed in
(just gone dead) -- exactly as predicted by An Expert on the DIY group.

Mine is just such a cheapie from the same shop at the same price. Except
that it has lasted for years despite horrendous abuse (like being left
outside unprotected over winter full of water).

Christian.