72 is a different key to 70 71, the 72 column has a locking feature, the key is longer and thinner.  The short fat key 70 71 style is still required for the boot

The parts book lists 72 with and without steering lock.  If yours is the non locking type the Lucas barrels sold for mini, mga, mgb etc are a direct fit.

Thanks for all the help guys. Problem solved. I jimmied around with the lock and put some graffite in it and now I can turn the car on with my house key and virtually any other key around the place. I'll have to add another kill switch to be safe. It appears I don't have a steering lock.  Thanks again.