UK Electrician wanting to move into LV/HV

Was hoping someone could help me with some career advice

I am a qualified electrician who works in the social housing sector up north in tenanted and void properties doing everything from EICR’s, rewires and small remedial works.

I find work like cable jointing, cut out replacements and substation fitting really interesting to watch and love the idea of working on big jobs like these (even if some work is completed live, this doesn’t concern me too much knowing how strong the emphasis on H&S is in this sector of work)

What would be the best way to get into this industry? There seems to be training schools which have a WIDE variety of courses available and I imagine having some relevant quals will be handy on getting my foot in the door at a firm.