We used Harts Upholstry over in Abby. Auto upholstry is their 'thing' and ours is done on the heavy duty scale, because I hate to have to re-do something over gain because it wore out, LOL!!! You might find them pricie (because they do good work??), but give them a call....
Ours was pricie mainly because of the cost (at that time) and quality of the foam which in the corners had to be built up (and is in some spots almost a foot thick) to fabricate a 'sofa' seat for us in the front of the
Trillium.