Very pleased to hear the news, although I think they've guessed that you wouldn't accept anything less. Distributors used to get about 40% off parts back in the day & I don't suppose that's changed much. Mind you, you never mentioned anything about a courtesy car - I hope that they had the good grace to offer one. Another thing you didn't mention was whether you had to sign some kind of 'work order' initially. I don't know the details of the Ts & Cs used in JLR distributors, but these often try legally to let the garage off any hook. In the UK, 'unreasonable' contract clauses can be challenged, but it all makes it difficult for the man in the street.
One thing for other people who might run into similar issues: Courts & mediators are much impressed by written evidence & hate 'I said - they said' as there's usually no proof either way. Had this not been satisfactorily resolved, my advice would always be to get as much as possible in writing asap. This does not have to be from the garage (or other supplier), although you should keep anything you have from them. You should write what I know as a 'Note for the Record'. This is a simple letter to the supplier, sent by Recorded Delivery. This is written as a letter, simply stating the facts in chronological order, but including what you were told verbally. Unless they dispute your account, it changes mere verbal statements into written evidence.