outdoors in a sheltered spot will bring 'Heidi Ann' through provided the pot is kept frost proof and the compost relatively dry. you could stand the pot inside another one filled with gravel/or some other non absorbent material to keep the plant from freezing. as for the other one you can do the same but perhaps add a bit of fleece.

Thanks, that's reassuring. I can put them against a South facing wall & I've got yards of bubble wrap

Also you can't keep the green shoots through the winter. Let it die back but don't cut off the stems until new growth starts in the spring. You can let it get dry - its wet that will kill it when the temperature is low. Danger with putting bubble wrap on too soon would be condensation so keep it for the pot and use fleece for the top if you have to keep it outside. If you have an unheated room in the house a tender fuchsia will survive there all winter if left quite dry.

Thanks Stera, it'll have to go outside but I've got a big wire container full of twiggy sticks & things I leave for insects. I could nestle it down in there & like most of us I've always got one eye on the weather forecasts just in case

That’s good advice for Swingtime, but as Heidi is hardy I think you can just leave her alone (but perhaps I’m mistaken?).

Well as you are further North it would be a good idea to cover it with a good mulch of something - dried ferns or bracken is useful for that.

They're both in one pot. Can't believe a big hairy bloke like me is worrying about pink flowers 😄 I should get back to the veg...
Is the Winter die back essential to the next year's growth?

Its a protection I guess. If the leaves are gone they can't get frost damage which could kill. They need to go dormant in our climate. They will know when its time to hibernate. But a tender one may not survive outside in a hard winter in any case.