I watched this as well earlier, pretty concerning. I've not seen much of the chaps content but from what I have, he seems quite reliable. I'm fairly local to Mclaren Manchester and in fact looked at a 650s there a while back. Sales team seemed alright on that occasion but then again that's no reflection on customer service and on-going interactions.
Was interesting to hear it seems dealer related rather than a brand issue. From what I remember he had very positive things to say about Woking. I hope Mac sort out the QA and also start allowing third parties to fix the cars as it's not helping them at all either.