I used the place near the airport many years ago - can't even remember the name now and they did a very good job.
There is an upholsty shop in San Juan. If I remember correctly you turn right off the main street just before the big Textile Sur shop and it about 20m down the road on the right. I know they do furniture - car seats - you can ask.
One person who may answer your question better than me is Richard from CVS Car Valeting and Servicing. Their work shop is aprox 100m up the Tamaimo road. His phone number is 627107052