Time for me to add to this thread. I had the old LH Amex/Visa card for a number of years, and it was great - my go-to card. Reasonable points earning, and MBNA back-office so it ran pretty smoothly. I applied for the new Diners/Mastercard set up almost as soon as it was available. Like some others here, it took an age to arrive, and there was a problem getting the PINs. They send them by text, but they had input my telephone number incorrectly. That pretty well sums up the mickey-mouse operation behind this card. You can only contact them Monday to Friday in office hours. It took many attempts to deal with the PIN issue because nobody checked the details. When I asked what the foreign currency charge was (reasonable for an airline card), nobody knew. Promises to find out and tell me were broken.
The cards themselves are somewhat strange. It is a regular Diners club card. The MC is not a credit card but a card which is loaded with money when you use it from the Diners card. In effect it is a prepaid card which you don't have to worry about loading in advance. The very first time I tried to use the card it was refused. Since it was on a Saturday, there was nobody to call to deal with the problem. Rang them on Monday and they told me that it was above the amount which triggers a check. The amount was £5k (well below my credit limit). I was told this would happen every time I used the card for this amount. I asked for the amount to be increased. Initially they said this could be done, but then cam e back and said that £5k was higher than they could authorise.
So there it is, a useless card for anyone who travels or who has expensive purchases unless you want to do all your purchases 9 am to 5 pm Monday to Friday UK time when the office is open to authorise a payment.