Just make sure the lock sits flush with your handle on the outside of the door, ie none of the lock poking out at all.
Deff dont get a thumb turn, as above very easy to open.
Easy job though, OMFG at the above £38+vat for the euro then £65+vat for fitting, anyone wonder where locksmiths tend to be labelled at very expensive/ rips off merchants. I would feel so so embarrassed if I quoted someone £120 to supply and fit a euro.
Cheers, Mike