What a joke,problem solved...
Instead of a couple of hours,try 5!!!! for a service!
When revoving and installing air box,the tubing also has another pipe leading into the engine.
This had come loose = low oil pressure
not stating can only assume air in lines
beeping and brakes warning,think weak battery.
So got mrs car (jump leads) n cranked till it started,least 15 seconds of pure cranking,then jumped to life
Took for a spin and all is good. What a day.