Our smart meter is fixed on an L bracket, in the cabinet. The L bracket
holds the meter by the two unions only, rather than supporting the
meter from below at the base. The rubber feet are some 2" clear of the
cabinet base.

I thought I read something about the regulations required it to be
properly supported, including a (second) bracket to support it at the
bottom?

Thing is, our latest energy supplier cannot access the OVO smart gas
meter remotely, so they have agreed with me to fit a replacement which
they can work with. I might as well make sure it is properly installed.