A lot of "sportives" seem to be creeping up in price and sometimes seem poor value when you compare with a club run (free), reliability ride (£5 ish) or a time trial (£8 ish).
But some, like the LTB are a bit special, not really a bike ride, but a real experience and perhaps worth it , especially if it's in a good cause. Have ridden it a few times, but the novelty of the LTB has worn off, and the ride back is a little tiring nowadays.