Ignition switch Woes..., tumbler not turning enough.. Options

[Rod]

Ok so the ignition switch was cracked and a replacement has been found. The problem is that the key part of the mechanism won't turn the ignition switch barrel far enough to make contact and turn the starter...

The switch works on the bench, but put it in the Ignition barrel and turn with the key and nothing..

If I shim it out with tape around the switch it works, but still intermittently..

The key part of the switch is also at the stage in life where I can remove the key with the ignition on! - It just near enough pulls out!

So are these available new at all, or do I start a second hand search? Also - how much of a hassle is it with regard changing door and boot locks to suit? (I hate having different keys for everywhere...)