Rogano has a champagne afternoon tea, though not in December. Don't know what its like though:

roganoglasgow.com/menus/afternoon_tea.html

If you are willing to travel a little towards the east then Hopetoun House near South Queensferry is a beautiful setting with afternoon tea offered.

The interior of the house is really interesting and the grounds are also lovely. It would definitely meet your desire to go somewhere that is not a bar setting.

http://www.hopetounhouse.com/index2.htm

I can definitely recommend Cromlix. Lovely setting, traditional decor and some lovely little touches.

Staff are all lovely, and there is usually a roaring log fire.

Emelda

Hi

Hotel du vin in Glasgow does afternoon teas, with champagne, but asks that you book a day in advance.

Fif and Ali in princes square in glasgow does delicious looking afternoon teas, again with the option of champagne, but when I last went there the service was really poor and disorganised so I wouldn't recommend them.

thanks guys, couple of ideas worth looking into I think.

Tried Fifi and Ali before and have a lousy experience with service so it's off the list I'm afraid.

Cromlix is an option, glad to have someone else confirm it's good.

Hopetoun House looks beautiful, the site suggests they are closed after September but they have a Christmas event at the end of November, so I'm going to call them and ask if we could combine both.

I'll keep you posted.