When I received mine, I thought there had been an error and they had inadvertantly put an extra zero in the indicated credit limit as it was so high.
I telephoned them to check, but they said it was correct.
When I recently rang to check on a missing item, they offered me an even higher limit. I thanked them, but declined the offer as I have never spent more than 5% of my existing limit - I only ever use it to pay for flights. I have other cards which give better rewards for other things.
BM