Am upgrading to OPS and the old sensor holes are 26mm, I need to open these up to 27mm, but most step drills are 26 or 28. I think 28mm will look awful and leave a big gap around the sensor. Problem is the only step drills I have seen that can do 27mm cost a bomb, and only to drill out 1mm on 4 holes is extremely difficult to justify.
Does anybody in the Midlands or Surrey have one they can let me use for 10 mins please?