Lost (therefore need to reset) the pin code for Matsui TVR185?

I recently plugged in my Matsui TVR185, TV and Video combi (that had been unplugged for some time) to be met with the message 'enter pin' ?
I was not aware anyone had set a pin up on this tv therefore suspect the memory/battery has drained
Is there a default number eg 0000 or certain key strokes please?
Thanks for your help