Lemon Tree Over Winter

So the question is- where to keep my potted lunario lemon tree over winter?
It was bought in late June and already had 5 lemons on it. They look like limes and have never ripened any further though it has been kept in a sunny spot by a warm house wall.
When I got it I repotted it straight away into larger pot using citrus compost. I have fed it regularly and it flowered well and has over 20 tiny lemons on it now. I pruned it last week as it was shooting out in all directions.
So when we started to get colder nights a few weeks ago and some stormy weather I moved it into my greenhouse.
The greenhouse is unheated and probably not much warmer than outside over winter. It would have a fig tree for company which I know is hardier.
Will it be ok in the unheated greenhouse? Should I wrap it in lots of bubble wrap, if so do I just do that now and leave it on until April or so?
Should I buy a fleece bag?
Ive thought about bringing it in the house. The house is always going to be about 19-20•. But I’m having trouble thinking of a suitable spot for such a big plant near a window. In front of my patio doors seems the best spot but it would very much be in the way.
What do others do with big citrus plants in winter? Also, how long for the fruit to ripen, they havnt changed at all in size or colour since June?
Pic of my pruned tree>

 

Hello buddleia64, cool, light and dry are the rules :-) An unheated greenhouse is ideal. If temperatures in your area go really low, e.g. -5C or lower, cover the tree temporarily with fleece and wrap the pot in bubble wrap or some other form of insulation. Make sure the pot is raised up so water can drain away easily and cut down watering to once a month or less if the compost is still damp.
The fruit will continue to develop, but they can take a year to ripen.
The tricky period is in Spring. Resist the temptation to water heavily if you get stop/start Springs! HTH...

 

Depending on where you are and what kind of winter we get it should be ok in the greenhouse.

Keep it just moist drying out a bit between waterings , you get used to the look of the leaves when they need a drink they go dull and not so shiny.
Fruit ripens all year round, pretty much, but takes a long time, even stops growing, then has a spurt and ripens.
What ever you do don't bring it into the house, it won't like it and probably drop all it's leaves.

 

Mine comes into the conservatory each Winter, usually around the end of October.
The Meyers Lemon (lemon/Mandarin cross) also comes in too.
Because it is heated I keep them moist as the temperature rarely drops below 8c even on the coldest nights.