I would agree with Mallorca but also enjoyed some riding near Nice recently, you can fly direct with BA from Heathrow on nice short flight then €1.35 ticket on the tram to the city centre.
I found Mallorca easier as the climbs can be substantial but not too long, but the Col de la Madone near Nice… It just killed me. Relentless 950m climb from spitting distance to the sea to the summit.
For Nice I found these two sites really helpful:
Good luck with the baby, that’ll shake things up, we have a nine week old boy at home! There’s some good wisdom on this thread re that particular life change 