Make life more difficult for criminals
A point worth making here is that we ought to be trying our best to make life more difficult for petty criminals. Stop, for instance, using copper wire wherever possible and run fibre to the individual household premises. Fibre is merely purified glass; expensive but the resale value of scrap fibre is as near nothing as makes no difference, whereas scrap copper once separated from the insulation and chopped up to make it unrecognisable does have a very real scrap value.
Similarly cabinets need to be better armoured and also need to stop running on 230V AC. So, for that matter, do streetlights. It may have escaped everyone's attention but we are currently trying to force every vehicle owner in the country to change to battery electric vehicles (BEVs). When we manage this, we will have perforce compelled the nation's petty criminals to use BEVs as well. At this point, working out how to steal electricity will become a knotty problem at the forefront of lots of admittedly not very good minds.
Easily-opened cabinets with recognisable UK plug sockets in them are an obvious and easy target, even if the power sockets do have fairly low-output fuses. Changing these sockets for a much less common sort, and even hiding the 230V circuits altogether and leaving merely a USB or 12V socket for the engineer to plug their kit into would go a long way towards heading off electricity theft from these cabinets before it ever becomes a known target.
Similarly running streetlights on much lower voltage at much lower, dimmer outputs would save power and remove street lights from the list of potential electricity theft targets. The same theme should be carried on elsewhere: remove the easy targets for theft of power and copper.