Thanks, that is helpful.
I am teetering between the Varifold and Volvo. I have various Volvo quote and all suggest the 16×11, not the 15×10 which is what Bruntons suggest for the Varifold. The best Volvo quote is rather cheaper than the Varifold, and the prop looks lovely, and I value your recommendation, so I am likely to go for the Volvo 16×11. I am going to the London Boat Show next weekend and both Bruntons and Volvo will be there, so I will make the final decision then! Thanks for your help.