The repeater may not be transmitting freeview, many of them are reserved for analogue until that goes. If certain channels are flakey on Waltham I can understand. Multiplex C and D are only running on 60% of the power from the transmitter the others are so I'd expect problems with Dave, E4+1, sky3, Sky News, Virgin 1, Film4, TMF channels like that. It doesn't seem to work out that way in practice though always. 50% is about what you need, lower than that and it starts stuttering and cutting out. Mind you the field strength seemed to be very strong in the central leicester postcode I put it, I can see why it might work on an indoor aerial.
You got any wardrobes you could put a log periodic aerial on top of, I reckon that'd work as there's enough gain where you are and it's promising you're getting decent signal strength on some channels.
You got any wardrobes you could put a log periodic aerial on top of, I reckon that'd work as there's enough gain where you are and it's promising you're getting decent signal strength on some channels.