Sorry don't know the answers to those questions, but I booked a weekend break (flight and hotel) in Club through British Airways Holidays over the telephone, and they will accept the travel shop vouchers.

From what I remember, they charge your credit card for the full amount. You then send in the vouchers and BA holidays then refund the voucher amount to your credit card.

The hotel price was actually better than anything we could find on the net, and the flight was about 25% cheaper than the equivalent on www.ba.com. Plus, as they don't have online booking, you don't get charged extra for telephone bookings!

Hope that helps.