Here we go again! Channels disappearing again, only to return hours later? I have 3 Freesat receivers, all are doing the same. Like I said new dish in the last year, new LNB last week. So, what is going on with Freesat? I am not going to pay a monthly fee. Getting to the point of just not bothering with TV anymore. In a Freeview black hole, so that is not an option.
Nothing to do with Freesat per se - if there was an issue with their transmissions, it would be affecting everyone relying on them across the UK & beyond including Sky customers. You would definitely be reading about it here & also in news reports elsewhere.
It's likely that something in your receiving setup has gone awry - saying that all the receivers you have are being similarly affected would generally point to your receiving setup not being optimised. If I were to guess, your dish may have become misaligned (all it takes is for it to go off-focus one or two degrees in any direction, and with some signals from the same satellite position being stronger than others at a given location, this can give the effect of losing some channels while retaining others, for now), or there might be a case of local interference causing certain channels to drop out at certain times, or if you're using a multiswitch to feed your Freesat receivers, it either may have gone faulty or one or more of the coax cables between it and the LNB may have gone faulty, etc. There could be many different reasons, and it could end up being more than one.
I'd be initially tempted to think that either the dish has slightly gone off alignment or that some interference locally is temporarily knocking out some channels, but without knowing the setup, what channels are affected, local geography etc. then it's a case that if you're not confident of your own capabilities of solving the problem at hand, even with suggestions made by the forum regulars here, then it is better to get someone in who very likely can solve it for you.