[non-Austin] any MOT specialist knowledge?

[A G Wood]

My sympathies Hedd! Before you tear into it can you see whether the cable rotates ? If it does the little plastic H shaped piece between the cable and the latch is broken for sure, we were told its a deliberate weak link to stop the hood latch being forced. Not sure why the hood area was made so secure. Only the battery is any use to anybody? My experience is usually that someone has braille parked/leant against your grille (it doesn't take much) and pushed everything back snapping the H. Accepted recovery procedure in the dealership was the 10mm ratchet spanner route and remove the latch, its not as bad as it looks,  but you do definitely need a hoist for that (and long-ish arms). If the lock won't rotate both ways its worth trying some CRC to flush the road dirt out especially if its a Tibbe type key (and make sure the key if its Tibbe isn't excessively worn). FWIW the replacement for the cable is/was a universally jointed rod.
Good luck, swearing is permissible, and indeed encouraged.