For the duration of Level 2 and the latter part of Level 1, we use the Unitas 6498 movement for illustrating the points in the lessons.
This is technically a pocket watch movement and a very basic watch to get started with.
However, the Swiss model of this movement is actually quite expensive and so you may wish to consider purchasing the Chinese clone which is available from many places worldwide.
In the U.K. You may find the movement listed on the CousinsUK.com website under the code: CHI3620M
On eBay, search for Unitas 6498 clone or Seagull 3620