Hi Rojie,
Van is already converted, it is a 54 plate, so is early model. It is a side conversion.
https://www.fantasticcampervans.co.uk/used-toyota-alphard-fife-scotland-4013964
Mileage is about 38000, so low (I guess).
The quoted clearance online is 157mm (so pretty good measurement by you!). I am not sure how much clearance I will need - I'm not really thinking of driving places I woudn't drive with my Vauxhall Zafira which has a smaller clearance. However, I think that what is concerning me more is the approach and departure angles rather than the clearance. I can't find data for those. The problem is the shape at the front which doesn't rise up as most cars do.
Looking forward to many a trip iin it (if I can pick up the courage to actually buy it!).
Ian