Thanks for your suggestion Helen. I put this your advice to the hosting company ( LCN.com) and received the reply below.
The support from LCN is generally excellent but this issue seems to be a real head spinner.
Any other responses from anyone near or far would be greatly appreciated.
I have received an update from our engineering team regarding your issue logging into Silver Stripe. They have tried to add the "Header edit Set-Cookie ^(.*)$ $1;HttpOnly;Secure" as suggested in the forum you provided but this is not allowing the login. They have also tried making a new admin user and that also did not resolve the issue.
They have done some research on your issue and they have found lots of suggestions about how to solve this but none of them seem to be working. They have provided the link below, saying this is the most relevant thing they have found:
I would recommend contacting Silver Stripe and seeing if they have any idea’s how to solve this issue as all suggestions we have tried are not solving the issue.
If you run into any further difficulties, or you’d prefer to talk it through to one of us, just give us a call. Our number is 01438 342 490, and we’re open from 8am to 10pm, Monday to Friday, and from 9am to 5.30pm Saturday and Sunday.
If there’s anything else we can help with, just let us know.