Method...
Put meat in slow cooker before anything else
Cut up vegetables + onion and place in slow cooker
Pour tomatoes over top
In a container mix together the water, gravy powder, bbq sauce and jam (dont stress if jam doesn't mix in.. it will while cooking)
Once mixed together pour over the meat. If more liquid is needed add a little more water over top.
Cook on high for 6hours or low for 8hours.
In my slow cooker, i have had a few issues with the vege not softening, so once I cut them up I boiled them for a little just to help the process)
I also added a little seasoning to give it extra flavour but that is your own choice :-)