I have been to Gran Canaria a few times, as my sister lives there.
Make sure you dont forget your European Health card, in addition to your travellers insurance. Also bear in mind that your travel insurance is unlikely to pay the private ambulance that restaurants, pools, etc, will call on your behalf if you get hurt (they are on commission), and the bill is from £200 and up. Just to be transported to the local private clinic, which COULD be 10 minutes away, or less.
If you go to the Aqualand in Maspalomas, be very careful, as they are not that hot on safety on the rides, and staff are rude and have no sense of customer service. My dh got a head injury there, because they had not gauged the speed his float came down the funnel, and he hit his head against the concrete stopper at the back.... They sent him by cab to hospital and got free ex ray and treatment, but, it should not have happened in the first place. And when it happened, I ran down to him, forgetting our bag at the top, as I had the kids in tow. He was taken away to the first aid room, the staff refused to pick up my bags at the top of the ride for me, because it was not their job to fetch stuff for their customers. So rather than going with my injured husband to the first aid room, I had to traipse all the way up again, with my scared and crying kids, while the staff shrugged their shoulders and chatted between them. Non of them were helpful in then afterwards telling me where the first aid room was, they just shrugged and carried on with their stuff.
The other drawback is that the pools are grouped according to age, which is fine if you have different pools age groups spread across, but all the young childrens pools were in one area, so if you have two children of different ages, you have to split up as a family. The younger children are not even allowed to dip their feet in the shallow pool (kneehight), because the rides in that pool are for over 5s only. Nothing really for under 5s. My son was 3. Horrible lay out, horrible place. Avoid avoid.
Sorry, that turned into a rant.
Also, restaurants are expensive. Lunch out was usually around £50 for two grown ups and two kids, and that was without wine and icecream, and rarely something "fancy". This relates to Puerto Rico, Mogan and Maspalomas tourist traps. If you go somewhere "off the beaten track", you can go into a pub and buy lovely baguettes for a £1 each, and 50 pence for drinks, or a supermarket to pick up food for a picnic.