Given that one machine is receiving OK but another not it reduces the likelihood that this is an aerial problem.
The EH60D is getting very long in the tooth now ... and all these machines eventually suffer from Capacitor Fatigue.
The loss of one multiplex ( ITV channels) is a typical symptom that may eventually lead to loss of all channels. IF this is the problem, have a look at
this thread.
But this can also be a problem caused by HDMI interference, either the machines own , or any other device connected to the TV via HDMI, could be the cause of knocking out a single multiplex.
Interference leaks from HDMI to the incoming UHF aerial leads causing this problem.
Keep HDMI and aerial leads as far apart as possible.
One definitive way to test if this is the cause of the problem is to remove all HDMI leads and temporarily connect the EH60D via scart to the TV and see if you get back the missing channels under those conditions, which, if you do, proves that HDMI interference is the cause.
Note that if the unit has been retuned whilst the channels were missing, they will not return without retuning once more when they are available.
In other words, if the unit has not yet been retuned , DO NOT retune it. Missing channels will return when proper reception is restored.