For Davebro:
Freeview signals are transmitted using a system of 'multiplexes', each of which is a bundle of channels transmitted together on a common frequency. The lengths of the elements on a TV aerial aren't random; they need to match the frequency of an incoming signal, so that they can 'resonate' with it.
So, in theory, you ought to have a separate aerial for each multiplex (as they all use different frequencies). That's clearly impractical, so any TV aerial is only a 'rough match' across the required range of frequencies and will inevitably be better at 'pulling in' some of them than others. That's why your aerial 'likes' some channels but appears not to 'like' others.
This table shows which multiplex ('Mux') is used by each channel:
https://www.freeview.co.uk/corporate/platform-management/channel-listings-industry-professionals
If you have trouble receiving one particular channel, it's highly likely that you'll have problems with other channels using the same multiplex.
To see the broadcasting line-up, listed by multiplex, for your local transmitter, double click on its name on the map here:
https://ukfree.tv/maps/freeview
(That link also shows the transmission power for each multiplex. On some transmitters the same power is used throughout but on others different power levels are used by each multiplex).