Quoted £650 to repair window seals - too dear?

AilsaCraig

When we have driving rain, water seems to pool at the window handles. It gradually starts to trickle down onto the window ledge causing some dark water marks. When our caravan was in for a service in April we were quoted £350 to repair the seals in all 3
front windows of our 2005 Bailey Pageant Champagne. The dealer cold not carry out the repair at the time as the caravan needed to be under cover and they were too busy with servicing and had no space. We decided to go ahead with the repair this month but have
now been quoted £650. This seems rather expensive to me as I have researched the cost of the parts, however I am new to caravanning and would welcome any opinions as to whether this is a reasonable quote.