oil light flashes and buzzer comes on!!!!

hi can any one help, it all started ages ago the oil light just flickered or glowed very dim, on and off, and over a period of time has got worse.

any way started car up today as it has been layed up for a bit, and the light was flashing on and off and the buzzer was on( seemed to me like a very weak buzz tho) so i turned the car off immediatly, then i started the car up again and it was still doing it, but i looked down  at my vdo gauges and the oil pressure was 6 bar, so i turned it off and just turn it back on to just the ignition and the buzzer was on!!!!! without the car running!!!!

then i ran the car for a short period, and the buzzer went off then on and so on then the light flickered then flashed!! then went out then flashed!! when it got to working temp the pressure was just above 2 bar and the light still flashing.

the cars done 75000 miles and i replaced the oil pump when i had the sump off. i have only fitted my VDO gauges recently (could i have upset something? i fitted the dual pole sender in the cylinder head is this right?)

however the cars oil light has been flickering before they were fitted but the buzzer never came on!.
 
any body got any ideas what it could be? and also how to fix it as the buzzin is started to cheese me off a bit!

many thanks

Chris L

might be a blocked breather hose allowing the engine to build pressure.
if your lucky. pull it off and have a look inside it. it will most likely be full of white gunge.

is that the one coming from the top of the rocker cover back to the air filter box????

yep