Hi Ian. There’s a reason Land Rover is infamous for unreliability…
Business use vehicles are not covered by the Consumer Rights Act, so the rights of the dealer to have the opportunity to resolve the problem are irrelevant.
You’ve had the car a year now, so rejecting it will be difficult even though you have had ongoing problems with it. You can become the most annoying person in the world, spending all day chasing the dealer, the finance company, the manufacturer, Trading Standards, consumer affairs programmes, and bash out email after email until they eventually give in – or get a lawyer. Playing nicely is not likely to help you now.