To add on from Darren's comments - the view with and without the UHC is markedly different. The nebula is visble in the 12.5" without the filter, but the filtered view reveals the helmet shape very clearly. The conditions weren't ideal with some high level cloud so I didn't explore a range of magnifications. I used a 13mm T6 Nagler for 147x and this framed the object nicely. I will certainly return to this object at the next opportunity to try out different magnifications and for a longer inspection.
Thanks to Mark (Hodson) for supplying the observing site and for printing out a finder map when scans in the general area (from memory) failed to locate it
