Loving my Hornby Class 50. Brilliant with SWD sound chip. But there is a screeching noise at anything other than minimal speed and this is drowning out the sound chip! Seems to be coming from No 1 end bogie? Tried lubricating with a good oil, as per Hornby Instructions. Made no difference. Noise similar to the old 80s Hornby Ringfield screeching. Anyone had a similar problem? Any suggestions? Don't want to have to withdraw the loco as per BR! Many thanks.... John