Wonderful! Thank you all for responding.
Perusing this, and other forums, I always find it interesting to read the variety of responses to conundrums such as the one I posted. Reading the responses to my post, it would seem that the general consensus is QR owes me nothing and I was lucky to get to London with only a few hours delay and no need to buy a new ticket from ARN. I largely disagree with this but I posted to this forum specifically to invite other opinions. I think/thought that 95 mins to connect at ARN when there was no bag to collect and recheck would be tight but adequate. I appreciate that there was risk involved because of the 2 separate tickets. My issue was the reason for the delayed inbound flight.
Anyway, thank you to all who have responded. Your responses are helpful in deciding what (or what not) to do. I hope my post will help to educate others just as posts here have educated me.
Thanks again and I wish you all seasons greetings and a happy new year! :-)