Thanks for the reply,
I actually got the idea from the site you mentioned -
I am looking at buying the Woodpecker Unilift and saw this and just wondered if anyone had / used one.
It looks a new design and is obviously aimed to use the US fixed base routers.
i have used one, but the rise and fall guides are in imperial, which is annoying. so i tend to use the trend measuring tool. it is a very nice piece of kit expertly machined out of aluminum and very simple to use.
it is important the table top is perfectly flat with the router lift. i think its a very useful tool for when you cant be bothered to set up the spindle to do a a small groove or rebate.