How do you get out?

When I registered at Commons Wood CC site, the warden raised the barrier to let my outfit in, I continued around the site until I found a pitch I liked, and set up my caravan. Later on, I returned to the office, reported the number of my pitch and was given a barrier card.

I didn't want to go out with my car until lunchtime the next day. I drove up to the exit barrier, swiped the card on the sensor, but the barrier wouldn't rise. I tried several times, but no luck. I reversed my car out of the way, and walked to the office- it was closed for the warden's lunchbreak. 

I returned to my car. Two other cars came up to the exit barrier, the drivers swiped their cards, the barrier rose on each occasion. What was happening? I walked to the barriers. I tried swiping the exit sensor again- nothing happened - with nothing better to do, I swiped the entry sensor - and the entry barrier rose, paused, and closed.

I then tried the exit sensor - the barrier rose, paused, and closed. I then tried the exit sensor again - nothing happened!

It then dawned on me what had happened - the card had not been activated on the entry barrier sensor when issued to me - and since my car had not 'officially' entered the site, it could not be allowed to exit!

So, on foot, I again swiped the entry sensor, saw the barrier rise and close, then got in my car, drove up to the exit sensor, swiped it, and, hooray! the exit barrier rose, I drove out, and finally went off to visit Shaw's Corner National Trust property, as planned!

What must have happened at all double barrier sites I have visited in the past is that the security system was alerted that my car had entered when I was given the swipe card, so it was then ready to let it out again. 

I thought I would write about this, in case it happens to anyone else!