Do I Need Permission

Certainly in my area, (assuming that your patio is not catastally considered a 'room'), you would need a full planning permission for this, as you would effectively be enlarging the house. There may be considerations which could mean a permission would not be granted. The fees payable to the comune will not be small, and you may come up against some (superable) difficulties with insulation levels or heating provision. I'd speak to your geometra about whether you need a permission, whether they'll give you one, (or whether he thinks you could do it in the black as it were) and get a preventivo from him covering his fees, the comune fees, and any other potential fees payable for heating engineers and thermal certificates and other bollocks. Good luck with it.

Yes, you would need approval. 

If you put in folding glass doors - ie something permanent yes you will need permission.  If they are plexiglass panels which clip in, then they are temporary and you dont (theoretically) need permission.  It all depends on how permanent your solution will be. It may be that your comune has a bylaw which allows you to close verandah's /patios - by paying a tot per square metre.  Round here its 57 euros psm at the moment, and then you can put in a permanent thing.   

Thanks for all the help.Look's like I'll have a chat with my Comune first.