I've got a different perspective. Our family moved to Harrogate six years ago, and love it, can't recommend it more highly.
We didn't have family or friends there, but it's worked out well. We live in the Cold Bath Road area. Kids in primary and secondary, two dogs. Yes there is rush hour traffic, but what town doesn't? We walk or bike every where, work from home a bit and commute to London as well so don't use the car much at all Monday-Friday. Harrogate scores high for walkability if you can live close to the town (very much achievable with your budget). Many local independent shops, lots of after-school clubs (sport, drama etc) and the older kids can cycle around to see their mates across town. It's a safe place for teens to push boundaries and practice teen-ing, and Leeds and York on the doorstep when they're old enough. Several top state schools. Local buses and trains are good too.
It's friendly, rich in culture and events - a stream of literary, food, beer festivals, two brilliant theatres, galleries, markets. Beautiful place, very green with gorgeous parks, woods, the Stray. The Turkish Baths. And it's a stone's throw from open countryside - we often spend weekends walking in the river valleys, Dales, Moors or at the coast.
We've found folk here to be very welcoming, didn't struggle to make friends even in middle-age, and the population is becoming more diverse. Growing levels of social activism and engagement esp around climate, refugees, homelessness. Harrogate will likely get a new MP in the next general election. No probs seeing GP. No NHS dentist for adults but that's neither new or unique to this town. Had some minor ops at the hospital and it's been fine.
We've lived in many other places in the UK and to be honest I'm always surprised to hear people complaining about Harrogate as its got to be one of the nicest places to live in the UK. Many people in our country would give their right arms to live here (and would suck up the traffic too as a small price to pay). New blood coming in (yes including Londoners!) brings new energy. Feel free to DM me if any questions and good luck with your search, OP.