Haterall Hammer (17th Feb) is a straightforward up and down from a pub. No real nav needed.
Tor y Foel (18th March) might also suit. Both give a good idea of what "short" races are like and are in the Black Mountains/Brecon Beacons, close to campsites/pubs/B&Bs so easy to make a weekend of.
The winter races in Shropshire are challenging, but the summer series races are much more beginner-friendly.