Just looked at travel city direct, cannot get flight from Glasgow as no availability but flying from Manchester on 5th May, a 3 bedroom villa near Disney and a full size car comes out at £3313 for 4 adults and one child. This should give you an idea on how reasonable your quote is.
Having said that Homewood suites is fantastic with the free drinks and Snacks Monday to Thursday and the free hot breakfasts.
Just found another one £3159 if staying at 3 bedroom town house at regal palms.
I have stayed there and it is excellent, Nice pool complex and Club. Situated on Highway 27, 20 mins from Disney