My new greenhouse

I have been looking at greenhouses on Gumtree and so far most of then look rather sorry for themselves and unloved.  I had more or less given up and then decided to have a look and I found an ad that was a week old.  Thinking that it was probably too late I took the plunge and called the number.  The lady was really nice and told me that she and her husband were moving to a smaller property so couldn't find a home for it.  It will come with staging and capping bars for the glass rather than the W clips.  They have the original receipt and instruction manual and from what I can see it looks in pretty good condition.  The owners are on holiday for two weeks so I can't visit it yet.

I'm a little terrified at the prospect of dismantling it although the owner will help.

I would like to have a slab base and will need to get a person in to lay that. If I was mad enough to lay slabs, what kind of surface would I need to lay the slabs on?  I will be cutting a outline from a compacted lawn.   Would I need hardcore or a bed of sand? Also how long do I wait for the base to settle before the greenhouse can be erected?

Advice much appreciated!