If that figure of 5.5k for monthly rent and rates is true and accurate, then don't bother. You simply cannot sell enough visits to make money. Lets say you figure a combined spend of £10 per person (£5 admission and another £5 in the cafe/shop), then obviously, you need 550 visits per month just to pay the rent and rates. Based on a 31 day month, thats around 18 visits per day, every day.....
Now, 18 doesn't sound like very much I know, but its actually a massive mean average figure for a skatepark in this country.
Off the top of my head without really thinking about it, I'd say you'd need to either double the amount of visits, or double the spend per capita, or any combination of the two. That would yeald 11k a month, and from that with everything paid, there might be a wage in it.
Corporate sponsorship or charitable donation is really the only way to keep a park alive in this country.
In answer to Evamedias question - do any parks make money in this country - I'd say that the only one that did without any assistance, sponsorship etc would have been sk8&ride in Bristol. Now known as Motion, it started life as two businesses with the owners putting equal weight to both sides. The two sides were the park, and a licensed bar/restaurant.
Midschoolers will tell you, it was a cool place with really nice owners. Some cracking sessions and jams to be had there, along with a beer and a bloody good meal.
It is my belief that it was sold as a going concern, with the two owners moving on in life quite nicely.
Of course, there is another way...
If you're a rich businessman and you need a tax loss, open a park and simply nick the cash out of it.