Tricky situation…
I had similar with a well known northern Lotus dealership about 15 years ago, where they wouldnt return a (refundable) £3k deposit, they kept promising it, but nothing was forthcoming. In the end I went to the dealership and wouldnt leave until they electronically transferred the cash to my account and I had verified it with my bank. They went bust shortly after this.
Just get down there and cause a scene until they pay up (electronically – no cheques allowed)
If they go bust before they transfer the cash to you, you’ll never see the money.
PS – If this is a defender ‘specialist’ , please name them so I know who to avoid.