Chris and Tracy are talking about freeview channel 8, i.e. London Live, and the old Now TV box that has the additional terrestrial station feature attached, which as you know is no longer in production.
I checked London Live this morning and it was OK, since I do not have that old Now TV box I decided to leave this thread alone.
So unfortunately, either Now TV help has to solve this problem with the box once they're aware of it, and fix it via an update, or Chris and Tracy have to contact the TV station's help section.
However, Chris and Tracy will have to explain their problem with a bit more clarity.
The Local multiplex is transmitted at a lower power so your setup with the NowTv box is struggling to receive this lower strength signal. Whether this is down to the receiver in the NowTv box or how you are splitting the signal from your aerial given that you mentioned you are able to get good sound from another Freeview set up you have elsewhere in your house?
You could try swapping your Freeview equipment around and see what results you get. Does the NowTv box give the same result in the other room, etc?
The more I look into it, the more I think it is the London Live channel itself, I have two of the Now TV/Freeview boxes, its the same on both, they are both completely up to date, the other stations that are on channel 35 are fine, Sony, Sony Movies, etc
The NowTV stick doesn't provide any access to Freeview. Your kitchen tv either has another device attached to it that has a Freeview receiver or the tv has its own internal receiver. What is the aerial plugged into?
Either way if you are using the same aerial for your kitchen and bedroom the signal is being split which may be the cause or if you are using two different aerials then then that may explain the difference.
Also, Freeview receivers vary in their abilities and the one in the kitchen may be better than the one in your bedroom.