T25 ignition barrel or is it? Help

[scarysteve]

I have a VW t25 1.6 Petrol air-cooled Hi-top. The locks are all worn and I am slowly replacing them with new ones. When it came to the ignition barrel I thought it would be an easy transplant. They only cost about £8-9 so I bought one and then found out how to get the old one out - no prob's but only to find that it doesn't match up. The code is the same - 411-905-855C but it is shorter ie, it doesn't have that long skinny bit protruding from the bottom. See image attached.Can anyone help me identify this and where I can get a NEW replacement? Many thanks