Got back from China last Friday with JY and I have to say it really was a great experience. John the tour guide was extremely helpful and had some great stories to keep us amused. He has been travelling to China for over 20 years so is a great help all round. The Chinese guides speak excellent English and make sure you know the history and sights to see .. all in all a great and interesting experience.
As far as money is concerned all 3 hotels you stay in will change £20 notes to Ruan (as long as they are not marked) and I used a couple of ATMs in Chengde with no problems. Since all excursions and meals are included you only really need maybe £20 per day to cover drinks, photos and any shopping opportunities although it is easy to spend more if you want (on jade, silk etc etc.) but most big shops accept cards.
Enjoy the totally different experience of China ..... Pete