Hi Bennett
To some extent your QQ are about the legislative timeline.
So there is a good summary at History of Asbestos Law & Regulations (oracleasbestos.com)
I have no connection with the authors of that page!!
But it tells us that the duty to manage came into effect in May 2004 (which is a date which I would have needed to have checked) BUT of course there was plenty of notice in advance with a consultation document before the 2002 Regulations and then a period of grace before that particular requirement came into effect.
HSE guidance says that you can reasonably assume that a building constructed after 31 December 1999 should not contain Asbestos Containing Materials. Frankly anyone using ACMs in 1999 let alone later would have been trying to get rid of whatever remaining stock of ACMs they already had.
Which I think largely answers your Q2.
As for Q1, the occupier of a warehouse should have been doing something to demonstrate that they were managing ACMs from 2004 if they should have had any reason to suspect that they might contain ACMs but not otherwise, but you should not assume compliance with the requirement.
It is always entirely possible that a warehouse might have been operated for the 18 years since the duty to manage came in without any reason to need a demolition or refurbishment asbestos survey as described in HSG264 which I am assuming you have looked at - if not, now is the time!
Let's suppose a warehouse was built in the 1980s - even that far back it is unlikely to have much in the way of ACMs except for certain elements which are highlighted in HSE guidance.
But as example, the warehouse might have a cement roof, which should ring alarm bells. But it would be unlikely to have ACMs in the rest of the main structure.
The floor is probably solid concrete. You might have some floor tiles in the offices with ACMs either in the tiles or in the glue sticking them down. But the options for where the ACMs might be are relatively limited in such a building.
Which then indicates that if you commission a Management Survey, a competent surveyor SHOULD be able to assume the ABSENCE of ACMs in most parts of the structure. Hence not much sampling needed.
If much older than 1980s there is much more room for doubt, so more sampling is likely to be appropriate - but with the recognition that a Management Survey to HSG264 need not be doing intrusive investigation into areas which are unlikely to be disturbed UNTIL the building is altered or demolished.
Even then a refurbishment survey only needs to do intrusive investigation in and around the parts of the warehouse that are being altered.
Final point! Each of these warehouses should almost certainly come with the health and safety file demanded by successive iterations of the Construction (Design and Management) Regulations - so if you haven't got a CDM health and safety file, that is something to be asking the landlord for.