I've been to both parks and they are good. Unfortunately I didn't see any private rentals like Haven sites etc have in the UK.
I think canvas, eurocamp, keycamp siesta holidays, haven and now even thomson alfresco do stuff in either 1 or both of these sites. Mind you it ain't cheap! You can also look at the campsite web sites.

I would certainly recommend flying and then hiring a car, you'll find this doesn't cost much more than driving, by the time you've paid for overnight stops. Mind you that's my opinion you may feel differently.

Thanks for the information. We have booked a chalet in Sanguli direct with the Campsite.

We are flying into Barcelona and going to use the train to get to Salou.