Having just thrown away my second professionally made cover I have gone down the DIY route. Professionally made are very nice but at £500 a go, expensive although each lasted about 5 years. Watch the colour though. Dark colours are bad news in the summer as the boat and tubes heat up underneath, not good for petrol in the fuel tanks as it goes off dead quick. So the DIY route is via:
cost for 7 x 4m was £46. Needle and thread from Chandlers and a day sat on the garage floor. It fits exactly is waterproof and being the h/weight material hopefully will last a few years.