Hello Jack,
Welcome to the Forum.
The problem here is that there is more than one supplier of pop-tops.
Differing tops may have differing heights.
Some owners change the wheel tyre combination from the OEM to something more appealing.
Most times, this will affect the vehicle height too, albeit often lowering the overall height.
It may not just be your work vehicle park you need to worry about either.
I live by the coast.
All my local car parks have height barriers (to prevent motorhomes and caravans).
My van stands at 1.94m. The barriers are, supposedly, 1.98m.
It can be dangerous to assume the height notice is accurate.
The entrance may not be level,
Some barriers are fixed, but can still be 'altered' by minor mishaps.
Others have a movable notice which are frequently hit by optimistic (or could not care less) vehicles, especially those with roof bars, kayaks, windsurfers, etc, etc.
Does the height notice remain accurate ?
And last, but by no means least, are multistorey car parks.
Notorious for actual height projections that are less than the posted height.
Having said all that 2.1m is not particularly low.
If in doubt, park elsewhere.
Good Luck.