I've used aluminium warehouse several times for my current build and they have been great. Good finish and accurate.
They did send one large block incorrectly (a big piece about 100x100x250 is what I ordered but I received a round block 100 dia x 250)

Phoned up to ask what to do and they said just keep it. ~2 days later the square block arrived FOC. I was pleased with that as it was ~£40

Might be a prototype spindle cartridge housing for the drawbar/ATC project in the distant future

They do regular and ecocast and prices not too bad

I know others have been unlucky in the past but I've not had a bad experience so far and would use again

So get all the experiences together and make a choice . . .