Hi Tom, I am sorry to hear that you are still having problems with your sky system. I use Freesat and I haven't had any of the problems with the channels you mention. Alan our Sat engineer had been in touch with James and he has discovered that we occasionally loose signal because of a burst microwave transmission that hits the West blocks dish. We are going to be having a discussion about possibly relocating the dish. That said this issue generally effects the system for a short period and then it should revert to normal service. To my knowledge all the upgrade work has been completed. This suggests to me that perhaps there is an issue with the wiring specific to your flat. I shall draft up an email to Alan Kay and have him liaise with you to try and establish the exact problem and find a solution for it.
As an aside I did note that the time of your post was during yesterdays thunderstorm and that could have had an effect on the system. However I just tested all the channels on mine and they were fine.
All the best