Doug
you should have asked for them to put some brains in as well mate.
Inverts are the correct way, you know that.
The cylinders only went valve up cos the original dv was on the tank and it made for long floodable hoses if valve down, so because of a design limitation they went valve up in the old days and nobody has ever questioned it until the (we) enlightened group put them on correctly.
See the anaesthetic hasnt dulled your fingers.
Rgds
Matt