According to 'Streets of Douglas - Old and New' by Stuart Slack:

"George Street, Great

This was the early name of the upper section of Nelson Street commencing at Prospect Hill, where the older generation will recall the policeman standing on point duty, and concluding at the old Adelphi Hotel, which stood in Church Street just below the present entrance to Shaw's Brow Car Park."

As Nelson Street is still there, in two parts, you should be able to find it on a street map, if you have one. I don't know if there is one on the net. If not, then I hope this helps on your next visit. S.