Waterproof Door Lock

I have a lock on my waterproof door to secure the van door a liitle more against entry.
I used a Master Waterproof Lock No 911 it has a Boron Alloy shank and is reasonably hard to pick. The Cames door can be opened easily it only has plastic tongues holding it locked. Lock is about $75 or so.

Proceed as follows .... Close waterproof door .... measure halfway between holes drilled for "T" handles (approx 400mm) and mark. Measure in 20mm from edge of door (edge closest to rear of van. Where lines intersect pop a centre punch. A 10mm hole needs to be drilled through door and angle attached to van ( put 'T" handles in to secure) for lock shank to pass through. Use a pilot drill to drill hole through .... when using larger drill sizes a pilot hole is used as a guide, the pilot drill should be no greater than 30% of the final diameter, so use a 3mm drill for pilot. Drill 10mm hole deburr edges .... pass lock through from rear. Check door seal before you drill as the hole might just touch seal .... adjust hole position accordingly.
I'll try to post a pic ...
Anthony