You don't need to go down the flex wing route to fly microlights - though you may find it cheaper to continue flying thereafter if you do fly flexies.
Most training schools can train 3 axis (conventional stick and rudder aircraft) or flex wing - indeed at your location (Herts?) Plaistows farm near St. Albans train on flexies and three axis.
Dunno the training rates there but budget for £80/hour.
You will need to buy your own aircraft (or share) to continue flying microlights and second hand flexies can be had for £3,000 upto £20,000+ they are easy to trailer and hangar and are an affordable route into flying.
3 axis tend to be a bit more expensive to purchase and run (due hangarage) though you can get wing folding and trailerable aircraft.
Tony