£55k is average for someone in the South outside of London. In London you can add £20k to that, and maybe another £10k in the City. (At least you could until recently.)

The answer is contract work. If someone can dodge IR35 rules and call themselves a "consultant" or a "solutions architect" they'll earn a lot more for almost identical work, with the useful option to leave gracefully if a project is toxic and on fire.

The other answer is to leave the UK. Engineering jobs pay much better in some EU countries, and engineering gets a lot more respect as a profession.