You can check from the vehicle registration on the DVLA website whether it falls into the £40k tax bracket, it will state Additional Rate Applicable until....
https://www.gov.uk/check-vehicle-tax
What specific parameter did it fail on and how far out?
Sometimes an oil change will help, particularly if the car is used on frequent short journeys which can cause fuel/oil contamination.
Assuming mileage was 10k or less since the last service, should be an interim service only.
The Lexus website details what specific tasks are completed, but an interim service is basically an oil & filter change, inspection and hybrid health check.
I was called unprompted by my local dealer today to have the protection plate fitted (no mention of cost and I didn't ask), so looks like things are moving in the right direction.
I suspect the only dealer option would be replacement wheels or they call in a mobile refurbishment service, so you would be better of shopping round for a specialist repairer.