We have just had a similar situation (but not with Motability). We ordered a yellow/gold Yaris Cross Dynamic from our local Toyota dealer in May and were told it would be available in October. In July Toyota changed the list of Yaris Cross models from 5 to 3 and removed the Dynamic. We were expecting the car to arrive in a week or so but last week we were told that Toyota would not be honouring our order since it was for a discontinued model and offering us a GR Sports model instead with a different choice of colours. This has completely different style (sports) seats which are uncomfortable & so not suitable for my wife. Surely they should have honoured our contracts since it was a valid model at the time that we ordered it.