Dear Pomtraveloap1, whilst I am not Chris, may I offer my opinion?
The belts deteriorate over time as well as mileage and the replacement schedule is 72,000 or 5 years whichever comes first. Even though your car has only covered 23k I would advise you to get the work done. My car had only covered 30k when the belts were changed and they had already begun to fray slightly.
I would recommend the following:-
Change the timing belt and pulley/tensioner.
Change the accessories belt.
Change the water pump. (Probably nothing wrong with the pump but they only cost £25 and add 15 minutes to labour cost if done when belts are already off, but done separately later on will need 3 hours labour and the belts off again.)
A good independent garage should do all this for under £250.
As to not doing anything at all, you are merely delaying the inevitable and at the same time gambling it will be fine. I would bite the bullet and pay the £250 because if you are unlucky and the timing belt snaps then the costs to repair/replace your engine will be £1000s not £100s.
I will be in the same position as you next year when my wife's Twingo is 5 years old. By then it may have covered 8,000 miles!
