Very, very poor. Had the flashing repaired, within 1 year it was leaking. After several phone calls (after each of which they said that they would be round 'tomorrow'), they finally turned up and said that it would be repaired the next week as part of their 10 year guarantee. After not turning up, I rang them again, and was told that I would have to wait as they were repairing it as a 'favour'. When they finally turned up they did the job but it was leaking again within 2 weeks. Now they are not answering my phone calls or returning my messages. Shameless cowboys. Do not use this company