a good quality respray will cost you a lot of money, materials are very expensive, just as workinghours
if you can get it done by an enthusiast, that doesn't have to charge full price for his hours, that will be a lot cheaper, but materials alone will cost you more than 700 punds
paint is around 100 euros a liter, you will need around 3 liters for a complete car, and the clearcoat, that's another 2 liters, but there's also hardeners, thinners etc
but the car has to be in primer too, that's about 40 euros for a liter
sandingdisks are very expensive too, around half a euro per piece, you will need a lot of them
a complete respray, especially with a colourchange, for 700 pounds can't be done to a good standard, materials alone will cost more than that.
When i make a quote to a costumer, it's 250 euro's per panel for paint, and then the hours for fixing dents, dismantling etc, hours are 80 euros ex BTW (that's the dutch equivalent for VAT) that's at my work
if i would take on such a job private, it will of course cost less, but materials etc will still have to be paid for.