I'm not sure but don't you plant garlic earlier than October? Did you notice any white furry stuff around where the roots should be? One of the problems with my allotment is White Rot in onions. The lack of development might suggest a poor clove to start with. If White Rot is suspected then this will not be the only one affected. The good news is that you only have to wait seven years before you can try again. Alternatively, I gave my bed a very heavy liming which did give me a reasonable crop.

I would have thought it was more to do with the rotton cold wet weather we have had this summer - summer - what summer?

Thank you for your help. Maybe Cammomile is right.
Will leave them until the Autumn, see what happens.

Around here, Elephant Garlic needs two years to reach full size, but it still should have been bigger than a marble. We plant them in September here, and usually expect a harvest the second March after. I imagine that in the UK, they will need excellent drainage, and as hot and sunny a spot as possible, with little competition from taller plants.

Thank you Tugbrethil ! With this news, + Le Tour de France starting on Saturday, I have now cheered up, as BBC is now churning out the Ping Pong (Tennis) most of the day for the Wimbledon Fortnight.
My Garlic bed has good drainage, and in the best spot for sunshine. Will leave until 2013.
Most grateful for your help.