Just an update on this
Went to a local Lexus dealer 2 weeks ago for them to take some photos of the blistering around the centre caps, said they'll send them off to Lexus customer relations for goodwill. As the car is 3.5 years old, the extended warranty won't cover alloy wheels, so there is no point making a claim to them as it'll just get rejected.
Didnt hear anything back since then on Friday i decided to ring the dealer to chase it up, been told Lexus have declined the claim due to 3 reasons
1- Car is out of manufacturer warranty
2- Didnt buy the car from new
3- Purchased outside the dealer network
So i phoned Lexus customer relations and explained to them this is a top of the range premium luxury car that costs £50,000 and for the wheel to corrode like this for such a new car is something unaccpetable.
They basically told me to fob off as i've just bought the car recently and it's a private sale, not interested in anything i say.