It’s a bit of pain in the **** to do, but if you’re happy getting mucky hands and arms, losing some knuckle skin and dropping the belt off the pulleys, a lot, it’s relatively simple to do yourself. I did mine and I’m not that accomplished with a spanner (had to borrow an 18mm).
You don’t need to take the front end off. Garage won’t for sure.
OEM Belts cost £16 ish and there are lots of YouTube vids to guide you.