Moto Guzzi oil leak - the Cure

Drastic action had to be taken to cure the small oil leak on the Guzzi Cafe Racer. I posted up some pics a week or so ago showing the pin prick sized hole on the inside of rear pushrod tunnel.  I had it welded up,but upon handing the head back to me,because of the difficulty to gain access, he did say "I can't guarantee to have sealed the hole"........... and it hadn't ! 
   The solution to gain access was as shown in the pics below. I brought it home,removed the guides - advised apparently because of the heat generated when welding up - and then set to with my drill.
  Got the welding done and my friend Martin machined the surfaces back. I put the guides back in and then had to get the valve seats etc re-cut.
  The oil leak is now cured.