The warden was helpful and friendly, the site was clean and safe with a good wash-block and it's convenient to walk to Denham station (1 1/2 miles) for a 22 minute train to Marylebone. However they are trialing an alternative power supply whereby you now have to register with an on-line third party electricity supply company, make a prepayment, and at the end of your stay they refund any overpayment. All sounds OK but it is a real pain as the website is very slow, kept freezing, and the main problem is the cost of the electricity which is extortionate at 47p per kWh whereas at home we are paying 26p per kWh; so almost twice the price for the electricity. The site is expensive at £33 per night but the cost for the first days electricity was an additional £12 even though the warden advised us to budget £7 per day which is probably an annual average. Not having electricity included in the cost of the site also means you have to check the App regularly to make sure you have enough money on the meter so your electricity isn't cut off which adds stress to your stay. If this system is rolled out across all sites it will definitely put us off using them.