As you've probably gathered by now our chances of reaching Ulanbataar aren't entirely guaranteed, so being the sensible chaps we are welcome to Plan B.

Thanks to the very generous chaps at Cogent Design Solutions we have our equivalent of Thunderbird 4; a fantastic Mezzo d9 folding bike, worth a not insubstantial £650. So when all else fails we'll at least be able to cycle our way to freedom, of course by 'we' I actually mean I'll be off to the border leaving Chuck to guard the car.

Therefore now armed with a spare plane ticket the bike is being repatriated back to good old Blighty and this is where you come in. We're offering you the chance to become the proud owner of a potentially slightly used but well travelled Mezzo bike*.

All that we want in return for this incredible opportunity is for you to donate to one, or both, of our charities. Of course we're expecting lots of you lovely people to support us so we've devised a cunning method to select the winner - what else but Guess The Mileage.

So after you've stumped up some cash just send us an e-mail with your prediction of how far we'll get, or add it onto any message you leave at Just Giving if you prefer, and who knows it could be you.

* we really are taking this with us and unless we have to use it in any emergency negotiations with bandits or border guards we'll be flying it back