If I need a plumber I'll phone my trusted joiner or plasterer for a recommendation. When contacting the plumber I tell him who recommended him to me. Knowing full well that plumber will then ask joiner " Have you worked for bazooka? " I have built a reputation as an excellent person to work for, very clear, particular, attentive and straightforward. The site will be clear and ready when they arrive; hot drinks offered at regular intervals otherwise I keep out of their way. The day they finish the job, I pay.
I'm in a similar position, @2bazookas , but I get recommendations from my trusted plumber. He's only had his own business for about 5 years, and he's already too busy to take on new customers. He did a few small jobs for me, then replaced my boiler, then a year later fitted a new bathroom. His tiler and carpenter were both excellent, and the chippy has since done a few smaller jobs for me. He also recommended an electrician who I have used a couple of times. I have an excellent plasterer, who I've known for years, and who I really trust.
My BIL has his own building company and he has great tradesmen, but they're all in E Surrey and are reluctant to come this far south. BIL is so busy, he's not even doing quotes for new customers and he's currently booking work for next July.
It's really hard getting tradesmen in the SE at the moment, and I daresay it's the same everywhere. Another Brexit benefit, I reckon.