Your still reasonably talking about a small click thru rate compared to page impressions.
156,000 odd compared to 5,000
I just done a look at one page for Northern Ireland on Weddings and one google ad was advertising singles in Manchester so in respects someone from NI isnt going to click so much on that
but...
they might if it looks like it might be a national company but non targetted google adsense doesnt help you much.
http://www.miva.com/uk/ type in unsecured loan
then type in hotel for that
More people would use google more than Miva but you can use a ratio factor on what people pay for adsense.
There are a lot of people that careful track adsense advertising, a lot of affiliates see when there best click thrus are clicks compared to sales and what time and change their adsense all the time.
Sometimes merchants dont do that, they just put on the ads and see what happens.
The website is pretty good and workable just checked and your number 3 in top 10 for whats on guide on google.
If you havent done anything for months on it, then your still reasonably doing ok on it.
Just done another search on adventure in the South West and out of four only one google ad was for an adventure holiday the rest were for cottages.
This is a factor as ok you might click on the one adventure holiday but not the rest but if you get pages that have non related adverts then it will generate less clicks.
You have the google ads in the right place, its visible people can see it so long story short
1) Low value adsense clicks
2) Sometimes adverts are wrong for the related pages