Hi All.
Thanks for your input on this issue.
In my communications with Met Office, they assured me that the long site ID was correct. For some reason it is now working. However, the link from Weather Cat to my WOW page is definitely wrong, they say, which is why it returns an error. I have tried another app (Weather Snoop on free trial) and its link to my WOW page works. I think somewhere along the line MetOffice changed the link path. I am not too concerned about this because I can go to my WOW page directly through a browser.
Cheers