It looks like a half wild honeydew melon, Bathgate. What do the leaves look like?

Thanks Tugbrethil Here is a pic of the leaves. I just took it now. lol

Yep, it's a honeydew relative, anyway. The closest match that I can find is the Japanese sprite melon, but it may be a hybrid of many types. If it's a sprite, it should be very sweet when ripe.

Thanks You.

I responded to this but my post doesn't seem to have been added.
Did you repost this as I'm sure Loosestrife added a comment too?

Yes I did.

that reassures me I'm not in the early stages of dementia then haha.