Hi Martin,
Firstly, I forgot to welcome you to the Lexus Owners Club !
Secondly, if you don`t buy this one, perhaps you will buy another Lexus.
Yes, you must ask the Dealer and keep a written note of whatever he says.
It is not unknown for Dealers to provide their own "arranged" M.O.T. certificates in order to lull the potential new owner into a false sense of security. They then use the M.O.T. to support their contention "that all was well when it left me Gov"
Have you checked the vehicles M.O.T. history and mileage? https://www.gov.uk/check-mot-history
If the work that might need doing has been done properly ,then you will be fine for several years, if not then if you discover that within 6 months of purchase you might be able to urge the Selling Dealer to fix at his cost.
The very low mileage if genuine might also be a worry that necessary maintenance has not been carried out, but let us know what you find out from checking the link I gave you above.
I do not know how much it would cost were you to fund the repairs.
Stay in touch and let us know how you get on.