Sorry,  more on  Grace my newish rescue dog (had her for 2/3 months  now).  Thank you for your helpful comments so far!

I have been lucky with Grace the Sheltie, my rescue.  She is probably middle aged and is it possible to teach an "old" dog new tricks?

I have persevered with the wee regime and she is much  more reliable now.  So I thought it might be an idea to take her to a training class (my old sheltie shone at obedience) but Grace hasn't a clue!  I think she has never done anything in her past life ie never had fun or played bless her,  she is such a solemn dog.  So I am trying to get her to enjoy a game or two but with not much response.  I really took her to training as I have always done this with my dogs over the years (usually  because they were naughty and need some training) but I thought she would benefit from a bit of socialising with other dogs.  The others there are mostly puppies and full of beans but Grace just seems to be puzzled by it all and not keen!!

I just want her to have a bit of fun - has any ideas on how to get an "old" dog to play?  One thing - she is very food orientated so treats do help!

As she is food orientated, clicker training springs to mind.

Some really excellent videos on Youtube by Kikopup & the Karen Pryor site is full of useful information

Hi, what about the puzzle toys you can get where you hide food I them and she has to search it out, just a thought.

There are some great boredom busters/puzzles for dogs on the market. Most involve food. Some are quite pricey but if you take a look at them, some are easy to replicate for a fraction of the price. Good luck!