Hauck Duett Tandem Pushchair - Black
Described on Mothercare here: http://www.mothercare.com/Hauck-Duett-T ... lt,pd.html
Described on Amazon here: http://www.amazon.co.uk/hauck-Duett-Twi ... B004BKQAHW
I've used this for my two daughters since the second was 2 months. They are now 3 years and 18 months and the smaller (top) seat is too small for my second.
I got good use out of it for 15 months - I don't have a car, so it went with me on buses and trains. It is shorter front to back than the three wheeler double buggies which makes it more suitable for buses. It is German-made, still in excellent condition and everything works well.
It is £228 new on Amazon. I am selling for £100 or nearest offer. Collect from Tooting Bec.