Need a bit of help guys. My Dingham auto couplers arrived today, I've took photographs and will make a mini write up in due time but I'm stuck.

Instructions say (in my own words) "If at all possible make sure the coupling protrudes at least 6mm's from the headstock outwards in line with the buffer heads. The coupler end must be inline with the buffer heads."

Problem is, even with the tabs removed and the coupler sunk as far back as it will go, and even after pulling the buffers out a little bit so that they look odd, it still protrudes about 1mm further than the buffers so really unsure what to do. Plus from headstock to buffer end it's about 5mm's but instructions said "if at all possible" so there might be lee-way, however, it isn't possible in my case with this 1st wagon.

Help please?