Hello again. Thanks everybody for the responses.
I have three questions.
1) Can anybody reccomend a specific speedo for 4wd's?
2) Can anybody explain about the saftey links in more detail?

I am happy to wait until Reading for those to be answered.

Also, a more general thing,
3) If I was to go and only do a 2WD robot, would I need to fit an axel at the front or just mount the wheels on?