Clockwise around the coast of the Isle of Wight takes some beating. Just keeps getting better and better as you go.
And as a Bristol lad, you might think of doing the "Windrush Winter Warm-up" audax route, which is stunning. Take a look at the Audax UK website .... you don't have to enter the actual audax in the middle of Winter - just copy some of their route. Come to think of it, most of the audaxes I've done from The Bristol/Gloucester/Tewkesbury area have been great routes. Someone else has done all the hard work of picking out the best, quietest routes for you.