Austin Hi,
H1s are pretty sturdy. But their tyres let them down at least those that were used back in 1996 when I had one in Beirut.
I may be repeating myself but managed to have three flat tyres on the same spot. At this was a plain field with some thorny bushes. But ordinary Toyota Corollas with ordinary tyres were able to pass through those bushes without any problem.
The H1 was useless about 20 Km away from there. It didn't not have a spare tyre as it was fitted with the automatic inflation system which is supposed to be able to accomodate three tyres losing air. And those tyres were supposed to be able to ran flat for about 50 kms at a maximum of 50Km/h speed. Did not manage to do so at all. And the H1 had to be moved on a flatbed.
I gave the H1 back and drove a Cherokee for the remaining of my visit there.
Take care Pantelis