HI Scratchcat
I only just found this thread and read it with tears in my eyes my own heartdog Holly is now 17yrs old and I daily have to self assess what to do and should I give her the sleep forever. I know I cannot put her through another winter . She was a very active working mate and although she has always slept in my bedroom she prefers to sleep on the floor ( I put a thick pad of blankets on floor and she accepts that)-not even a dog bed for her .I often wait till she's fast asleep to sneak a blanket onto her .
I have tried many things and Metacam is a great stop gap in the past, but be warned to administer with food, it can cause some nasty stomach problems. Shark cartilege (powder)from the health food shop got her through a couple of winters very comfortably (mixed in her dinner)
However, funnily enough she has the spirit of a lion, and exercise, very slow and not strenuous - we walk for about 15 mins in a flat shady park while our other dogs race around and do their thing, just keeps her bright eyed and eager even tho she looks stiff in the mornings - But then so am I till I get going. Can't stop the ravages of age but you can make her as comfortable as possible . Holly gets a kick out of going in the car so she gets a lot of that when I'm running around tho I do have to lift her in and out to reduce the impact shock.
I can tell how much you love her, you are doing as much as you can to help her -good luck with it all.