Helen, personally i would not go any where near either of these sites as they are a complete rip off, you can get far superior site for half the money if you do a bit of research on the web.
We use a lot of commerciall sites due to having two teenagers that need plenty to do and we have only ever used haven once due to the cost, we find the best way to find these type of sites is to use www.ukcampsite.co.uk and have a good read of the reviews then draw up a short list. obviously you will never get the best of facilities on these large sites due to the small amount of disrespectfull visitors that tend to use them but if you know what to expect then its not too big a shock.
In the past we have found hagens leisure to be ok, beaco fell view or solway, they are both a bit scruffy but completely adequate for a week or so, and almost a third of the cost of haven. we also find out of the very large operaters that park resorts offer good value for money, only 8 pounds a night at easter and round about 150 pounds for 14 nights out of high season, but once again dont expect the best of facilities as you will not get them, oh and avoid tye mawr in wales its awfull, its the only site ive ever suffered theft from. in truth you will find it hard to get a good site in the blackpool area as they are all over used and as a result very tired looking, theire is one site called windy harbour not too far from blackpool which i am led to believe is very good but when i rang to book the lady i spoke to was very arrogant in her tone of voice when i asked if dogs where allowed on site, she said in a very stern tone of voice that we do not axcept dogs at all, however others have told me that dogs are allowed, i probably called her on a bad day so give it a try you never know. We have just come back from another site not too far from blackpool which was lovely, its called wyre side lakes fishery and we had great weekend but its not really that good for kids, once they have walked round the seven lakes and played on the park they would be bored, we had no kids with us for the weekend so it was an adults only treat, wonderfull, great bar and fantastic owners. anyway save yourself a lot of money and give haven a miss have a look round and you will find far better, hope ive been of help. gary. (icemaker).