[londongardener]

I have this in an unheated greenhouse should I move it inside for the winter

[DD.]

I'm not familiar with it, but having done some Googleing, it seems as though it would be OK even outside!

One Amercian seller descibes it as "Longtime favorite…as hardy as can be! "

A UK seller says this "So often we have been asked by our customers for a seedless grape but as most of the varieties in existence will not thrive in the UK we have always had to say no, until now. Lakemont Seedless has been recommended by a leading Viticulturalist as being particularly suitable for cultivation in the UK and should thrive in all areas except for the far North, and is also suitable for indoor cultivation."

Which implies that it is usual to cultivate it outdoors.

So I would say that it is quite safe where it is. The end decision is yours though!

[gobs]

No need moving inside.

[DD.]

No need moving inside.

I think that's what I said!

[gobs]

It's nice to agree though for a change.

[mkhenry]

I have this in an unheated greenhouse should I move it inside for the winter

This was advertised by Marshalls in their 2007 Catalogue(I just cannot find a copy) they stated it was an outdoor varity but if grown indoors it needed a lot of ventilation.

So sold in this country for outdoors,it therefore depends how brave you are and how much you trust Marshalls.
Try to obtain a copy or speak to Marshalls themselves.  
I only remember because I read a post earlier this year and looked it up later.

[gobs]

There is no problems with grapes outdoors for winter down to about minus 15-20 C. Only reason they get caged here, is lack of summer. So they might fruit, no winter problems, at all.