I meant to ask him myself when he rang earlier to tell me. However, I was busy trying to stop DS from putting his head in the oven at the time, and missed the opportunity. When I rang back, he'd gone out of the office!
Anyway, according to him, we can renew our contract for another 6 months (we have lived here 2.5 years, and have never done this) and we have to pay 47 quid to do it.
Why?