I'm not sure if you're aware or not, but I think I know why Google is indexing these pages.
Right now, you are outputting URLs into your source code of your page in the form of a JavaScript function call similar to the following:
I believe this is because your page (and this function call) is programmatically created. Instead of outputting the whole URL to the page, you could output only what needs to be there.
For example:
Then change the signature of the JavaScript function so that it accepts this new input and builds the URL from your inputs:
function initSlider(price, low, high, category, subcategory, product, store, ajax, ?) {
// build URL
var URL = 'http://www.outdoormegastore.co.uk/' + category + '/' + subcategory + '/' + product + '.html?_' + store + '&' + ajax;
// continue...
}
Right now, because that URL is being outputted to the page, I think Google sees it as a URL it should follow and index. If you build this URL with the function in an external JavaScript file, I don't think it will be indexed.
Your developer(s) should know what I'm talking about.
Hope this helps!