Hi Bearcat - It is good to hear that you got somewhere but it was not exactly what you wanted and certainly does not make up for the hassle and lost files and folders.
Never mind phone calls and visits to back street shops. Do what you have done already and document everything. I would now write to the managing director of Acer and the owner of the business that dumped your disk drive.
As has been suggested, don't agree to anything until you have had some legal advice. Put your case to a lawyer and get an opinion based on what you have told us. It is not acceptable,I think, to be offered a bag of sweets on the assumption that you will now go away with a big grin on your face and be a good boy.
They ran you round in circles and palmed you off and then blamed each other. The sevice was poor to non-existent and it is my feeling that you should be compensated in some way for your time, trouble and loss.
You may decide to just leave it now and pick up the threads where you can but I still think you should get a legal opinion over this.
Glad you got somewhere at least.
My regards Doug