Don’t bother with an official Mazda dealership. the car’s way too old (and probably the mechanics there are way too young). You are better off using someone like MX5 City or MX5 Motors or Mazdadudes in Darlington. These guys will know Mk1 model inside out.
Lets not overstate the Mk1 MX5. Its an old, thoroughly conventional car sharing parts with the Mazda 323. No mechanic is going to be phased with it.
I take my Jag to a Jag specialist. He’s Jag trained, which means he knows no more than a Jag fitter, because that’s where he got his training. But, he charges more than a regular garage, because he’s a “specialist”. His fault finding capabilities are limited it sames. Same issue with the other Jag specialist in town. The best work on this hugely complicated Jag has been by a MX5 specialist, who’s actually a generalist (Thrussingtons in Leicestershire). I suspect because they run a race team, so have mechanics capable of problem solving rather than reaching for the local factors on speed dial.
The only possible reason to keep up main dealer stamps is because you have some cosseted MK1 with a 100% service history.
Never use Mazdadudes. Honestly, you’ll end up regretting it. Go search google for Mazdadudes and the top post is people who have had dodgy cars, work and parts from them.