John, I beleive the dealer can get a manual but I downloaded them from Lexus UK here:
https://www.lexus.co.uk/owners/about-my-lexus/manuals/#hero
and use the search tool as the UX doesn't appear on the list below.
The UX does have deadlocking on the second press of the key or door handle.
The door unlocking can be customised as per this extract from the manual, I left mine at all doors unlock so haven't tried it.