Gentle 50-mile around the Purbecks

This is my first 'big' ride for 6 years and I'm hoping to stick to an average speed of around 12mph (or whatever speed 12mph on my cycle computer represents). Hoping to break for a brunch stop of around an hour at Moreton. Only planned at the last minute but some company would be nice. Most likely will do this on my hybrid as there are a few hills and I'm not confident enough yet on a racer. For the route brochure visit http://www.bournemouth.co.uk/xsdbimgs/Purbeck%20Ride.pdf or google "Purbeck Ride"