There is a good chance if it's the weekend that they are closed. Usual proceedure is to ask three times. If you get no answer then you can go on through.
Is that true of all UK restricted airspace? I learnt to fly in Germany and was told that restricted means restricted
unless you get clearance. If you call 3 times and don't get a response, the airspace is
restricted. Reasoning behind this is that you could (theoretically) have misread the frequency, have an issue with your radio etc and could wander into a restricted area by mistake, thinking that 3 no replies means OK to enter / transit.....