Dog terrified of TV

[SmugOldBag]

We have an 11m old bearded collie cross. Rescue pup, had her since 6m old. Her background from birth to 4months is unknown
For the last few months she has been terrified of the tv. Before that she had no reaction to it at all. Would sleep happily with us in the lounge.
It seemed to start when watching Line of Duty, lots of 'mild peril' thriller style 'DUM DUM!!' music. Something like a James Bond movie will send her fleeing the room. Potentially it started around the same time as she experienced her first thunder storm which freaked her out and resulted in her hiding under the bath.
Every night after dinner she follows us to the lounge but as soon as the tv goes on she retreats to a back room which we feel pretty sad about. If no tv or we play just music she stays.
We've tried loads of things. Calm programmes (repeats of spring watch and antiques roadshow!). Treating her while she's with us with the TV on. Nothing works. She has one side eye on the TV waiting for something to scare her. At the slightest 'worrying' sound (wind noises, beeps, low bassy sounds, mild peril, even the Proclaimers the other day!) she legs it.
I'm unsure how to deal with this. On the one hand I feel she should do whatever makes her comfortable and we shouldn't force her but on the other hand I want to help her deal with these fears as it's clear she wants to be with us and a dog with noise anxiety probably isn't a happy dog.

Any suggestions?

YouTube ddoggy calming music. Our dpuppy was suffering even home for the school run post lockdowns etc. Lots of options on there. Some with still pics and some moving.

I’d probably try keeping the tv low for a while and randomly giving treats for her being around / maybe being mindful if you can of types of programme to avoid anything noisy.

she will get used to it and it might just take time for her to trust it’s ok it probably won’t be an instant fix

I'd also be tempted to try some classic desensitisation - it seems to me that the TV is almost made for this.

I'd have the TV running all day, on mute. Everyone ignoring it. In the evening when you want to watch it with sound, let her escape to the back room and don't make a deal of it.

Once she seems relaxed around a mute telly, have the volume on very low for a few days/weeks.

Then turn it up a bit when she seems ok with the low volume.

Then up.

Occasionally sit down to watch a minute or two when she's around. Then get up and carry on life as normal.

Keep building and keep letting her go to the back room whenever she wants.

At 11 months old now, my guess is she will stop bothering too much about the back room and this will quickly be something you look back on as a distant memory.