Hire car in spain costs

[floyd 1.8 turbo]

Booked to go to Alicante on the 16th of may. We need a spacious 5 seater, belingo for example. Theres me and the wife and the 3 kids. Cheapest quote i've got is £375 for a renault kangoo from amigo autos, used them before and there good apart from they slap another 100 euros on the total for fuel then extra for a car seat per day and your looking at over £500...not cheap.
Any help or suggestions would be greatly apprecited
Thanks