Thanks Gents for all your help. Due to a contact provided, we've cracked it.
As most of us said, the frame is Italian. It was made by a small builder called BIEMMEZETA based just outside Padova. It was most likely built in the 80s. They made frames that were sold to other companies to sticker, and well as keeping frames to be sold in their own name. Beware because there's also a food manufacturer with the same name!
The mark/logo/motif represents a bird in flight, and is not the dove used by Columbus. If you look closely, you see that it is slightly different from the Columbus dove. The dropouts were usually either Campagnolo or Gipiemme. They are supposed to be a good, solid road frames that ride well, and are very good all purpose frames.
Depending on their condition, their old mid-range frames go for anywhere between €20 - €245. I was contacted by a couple of US riders who use them, telling me that they are the fastest steel frames they have ever ridden, and very responsive to acceleration.
I won't be hanging an expensive groupset on it, but it will make a very good workhorse!
