The only ones not based I have are unassembled - which makes estimating height tricky.
Plus there's little consistency between IWM's minis over the years, and even within the new Classic plastics (Mad Dog and Awesome are decidedly oversized, but look so good it doesn't trigger my grumpy side ;) )
BTW, vehicles operate on a completely separate scale again. I did work out some equivalencies so I could scale some 3D prints of tanks I was having made. But vehicles work out at around 1:200, except significantly wider than real-world armour.
Mechs are supposedly 1:285, but one only has to compare to GHQ's accurate 1:285 vehicles to realise that's a little ambitious. The Classics may be somewhere like 1:200. Must do some measuring this weekend ...