logo design boundaries:
it should relate to the business field
(cars + Learners passing their test)
it should be simple to understand by the customer
(you can check this out by putting designs in front of people and saying 'DO YOU UNDERSTAND THIS?' - i.e.. not what do you think)
it should reflect the tone YOU want to portray
(warm and positive and approachable)
it should work in single colour
(i.e. NOT traffic lights, cos changes the cost of printing)
hmmmmmm, a little car with a smiling face - could it be that you've already got it?? Or even more specific, a little car with L plates/just an L plate on wheels with a smiley face???
The name 'Mr Smiley' - is that the business name? in which case, might need to put that thru the same test..
Don't know if this helps you, but would say it's NOT worth getting a logo on ebay when you sound perfectly like you've got ideas coming in.... may be wrong but.....?????