Gazz - I'm not stupid; two of my mates from the blind school are in this condition.  Of course there are a lot more out there too.  And you're right in your assertion re the fraud across the board - means testing and regular rechecks are needed I feel.

How many people are out there claiming incapacibility benefit for "bad backs" for example?  I bet some of them would be able to lift heavy items when moving house, for example. 

Johnhunt - good to know you're on top of the MS at the mo; a partially sighted mate's GF has this and her's can be quite variable - it's not a nice thing to have by any stretch of the imagination!