I’d get a price to run cable around your building if you don’t want to do the job yourself.
If you read the OP's first post it would appear that the OP's apartment is within an old mansion. The guest room is not his. It is a room that can be rented to all the apartment owners in the mansion. He can not run Ethernet cable along the shared corridor so it seems unlikely that he will be allowed to run Ethernet cable along the outside of the building or any where else outside of his own apartment
Hi:
You are of course correct.
In fact all is well now, touch wood - I've obtained a two-node Tenda AC1200 Whole Home Mesh Wifi System, and this has greatly improved the Guest Room wifi.
Many thanks for all your excellent assistance - you definitely deserve your "Distinguished Sage" status! :- )
Cheers
Brian Randell