Great stuff, thanks for everyones help so far. I've decided to get both the hollow tine and a small spike aerator. (managed to find the pair for the same price i thought i'd have to spend on just one of them!) :-)

How far apart (distance) do you recommend using the hollow tine tool? every ft maybe? Are the plug gaps big enough to put anything down to help drainage etc? sand maybe? Will this be of any help or a hinderance?

How regular could/should you aereate? especially the problem area? Ideally i would like to do it straight it away to help with the immediate problem. Could i then give it another go at the backend of the year as Steveo suggests?

Cheers, Mick