Lo,
The RAF seems to be very much a 9-5 Monday through to Thursday flying club. They also seem to stack earlier on a Friday than when I was in!
Given the above it is not at all uncommon NOT to rx any response from non-LARS stations in the afternoons, at weekends and on PHs.
Do as FFF says and you'll be fine.
It is quite tempting knowing that it is Sunday 0800 not to give them a call but that will be the day when they are launching a 4 ship straight towards you!
Give them a call - they are quite friendly and generally very helpful. If they ignore you or there is no response at least you know that you have done what you should have.
You will often then hear another a/c transmitting his details for your info, if I am in the same bit of sky, I will let him know what I am doing and then will call zone outbound.
Hope that helps, too.
Stik