Can you provide full line stats?

Are they using the master phone socket?

Are there multiple phone sockets in the house?

Is every device connected with a filter?

Is any extension cabling used such as this
Cabling

Do they know neighbour speeds?

Have you checked for fibre optic such as BT infinity?

I am working through the possibilities with my good friend but he is not too switched on about these things so it may well take time. The group of houses is more than a mile down a long "drive" in the middle of nowhere and it did occur to me why he did not look into the internet connection before he bought it!

Comments and advice much apprecuated and I will do some more checks when nextt there. At the last attempt we could not find the password to get into the router which had obviously been changed!

Neighbour speed are top of my list of checks.

Will report back but may take some time.....!!

TVM
Meldrew