I'm not brilliant at doing the vids as I've only got a phone. I will get some kit so I can submit something a little more professional.
Hers a little history. The watch was left to a friend by his father and was his great great grandfathers passed down to the next generation. My friend has never seen it running and it was left neglected in a drawer uncased.
The watch case and chain was totally tarnished almost black. I wish I had taken a picture. I had to work out how to strip the the works out of the case and found the little retainer pin at 6 o'clock which you have to push in to release the works and tilt up on the hinge at 12 o'clock. The movement was totally gummed up and very dirty. The chrono mechanism which hacks the balance, (the slide switch on the side of the case), was seized. The chain links were also very stiff. In order to split the top bridge from the bottom bridge I had to twist off the motion work wheel from the adjustment staff which is an interference fit. It was a touchy moment as I did not want to damage the wheel. Once I had everything stripped I cleaned all the parts in an ultrasonic bath using elmo degreaser. The chain was a task, I left it naptha then dried and left it in thin oil for 2 days. Wound it on a thin bobbin of wood to free up the links. After a few wind unwind ops the chain began to free off and I repeated the cleaning and oiling three times. No the chain is functioning perfectly. It is a long process and you need patience but the end result was worth it.
I cleaned the silver in lemon juice and cola. Washed in warm water then buffed with a jewel cloth. Didn't want to get rid of all the patina so left a few traces. Freed off the chronograph hack switch on the case.
Really enjoyed myself and the result was very satisfying.
Thanks to all here who gave me advice it was very much appreciated.