In view of atalnte83's post about bevel gearbox oil additives causing "clumps" of the oil I thought I had better check my BB oil. I replaced it about 600 miles ago with Morris XFS 80W/140 and added about 15ml of Liqui Moly MoS4, something that I had done as standard with a Moto Guzzi box I had once, as they specify. Not sure what Morgan used in the box but Liqui Moly doesn't seem to cause any "clumps". It all flowed well and seems fairly quiet, well as quiet as it usually is.