[Malcolm]

Recess the lift into the floor so that any low ground clearance cars can get on the lift. I can get full lift on mine with an internal max ceiling height (pitched roof) of 12ft and with the rear deck fully open. The recess I used was 9 inches.

Also try and get a copy of the lift installation drawings before you pour the slab so that you can get the foundations right. Saves risking a cracked floor later on when you lift a heavy car.

On the heating front I would avoid using a system like the gas burners (flame thrower thingy's) as this kicks out moisture and raises humidity massively. Use a dry heat source liek radiators or slab heating as previously suggested. If you do the under floor heating, don't forget to insulate the slab.

I wish I had arranged for a roof beam to take an engine hoist in my garage to avoid using a floor standing crane.

Not that you ever get car fires (!) a fire escape door or similar at the other end is sensible.

I would avoid the roof lights. Unless they are massive you won't get enough light to not use the lighting and they are a potential security breach and cost more to install.

Have you already got some external flood lights over your driveway area? I can't remember but useful for early starts!