Hello lovely Bramblecot....
We took a rammy lamb to the abattoir earlier this month.... they said they could take the horns off for us, and boil them in order to remove the 'inside' and then we could use them as we wished.... However, we were subsequently told that it hadn't been possible to keep the horns... We were told it was always subject to the approval of the vet....
Not very sure about this, but if it had gone to plan it seems that the abattoir are able to undertake the 'process' for you.... Let us know if you're more successful than we were!