Hello Andrew and welcome to the LOC.
I understand that Lexus UK provide a 12 year corrosion warranty but certain conditions have to be met for this to apply, I would either check these in your warranty booklet if provided or contact your local dealer.
Regarding recalls again your local Lexus dealer would be able to provide this informatIon, bear in mind they may ask for proof of ownership so take the V5C and some photo ID with you.
Also check the price of the cambelt replacement, Lexus offer a discounted service arrangement for cars over 5 years old and are quoting £295.00 for your cambelt change.
http://www.lexus.co.uk/owners/servicing-and-maintenance/#ServicingYourLexus