Question Oil Pressure Alarm Buzzer but no Dashboard Red Warning Indicator

[DCM-GBL-UK]

I own a Georgie Boy Landau 3425DS (Jan 2003) Workhorse Chassis in Scotland in the UK - 20 miles into a 40 mile journey back from a weekend's rally, heard piercing loud Alarm Buzzer but with no Red Oil Pressure Warning Indicator light from Dashboard BUT did have Oil Pressure appear in the warning screen on bottom LHS. Changing display modes - the PSI was 38 to 52 psi when driving at 50mph-65mph and 7-18PSI when engine idyling when back at storage yard. Leisure Batteries were in USE mode - but when switched to STORE with engine still ticking over, the buzzer alarm faded out. Q: was the 38PSI to 52PSI (with 60PSI sometimes) ok as a level for Oil Pressure and so perhaps the Oil Pressure Sensor could be the issue? Oil levels were checked before and after driving and so are ok - looking forward to any advice available - many thanks - DCM