H joan ive had two lemon trees outside against the side of my house (covered in winter)they are now 4 years old (about 50 inches tall ) as yet i havent had any fruit ,but its early days ,so fingers crossed.
i have also planted a meyer lemon down the bottom of the garden and am leaving it outside over the winter to see if it survives ok.
Meyer lemons are the most hardy, they are your best chance, and as you live further south than me that will be an advantage .
The other option of course is to have one in a pot outside in summer and maybe a conservatory or greenhouse over winter.
Good luck.

A friend keeps a lemon tree in her conservatory and it does produce fruit every year.

Thanks both of you for your kind contributions. Jake47: I shall certainly bear Meyer lemon trees in mind. I'm still not sure what mine is. I wonder how old you are. I'm not sure I can wait four years!
Shallabub: you didn't say how old your friend's tree is and how much fruit it produces.
Best wishes to both of you!