Fixing Vitavox GP1 Pressure Drivers

Hi, I have two Vitavox GP1 pressure drivers that unfortunately have gone open circuit.

Are these likely to be serviceable or are they beyond economic repair? I use them for public address at school fairs and other local events (as a volunteer, not for profit), so although it would be a shame to discard them, I’m just wondering if there is a chance of restoring them?

I did try Vitavox Hi-fi (Vitavox Hifi - Vitavox continues to build on this illustrious history hand crafting components to power some of the world's finest loudspeaker systems) but unfortunately they were unable to help.

Is anyone else likely to be able to repair (or replace) these please, ideally in the UK? They used to be fabulous for outdoor PA and my late father would be disappointed that I did not take better care of his ageing equipment!

Many thanks,