Possible - but wanted to make 100% certain rather than "any old bit of wire from eaves to master".

If it is then there could be a problem with degradation of the drop wire insulation.

Slow internet is not always caused by your ISP or by its technician.
Some time ago I had a similar problem. I changed to Virgin Broadband internet. When the all was installed a running I also thought that internet was a lot slower. But after some research in the internet I found out that the slow internet was caused by a virus that was installed on my PC (found the tip on the site slow internet). Removing the virus solved my problem!
So check also your computer if you are dealing with internet problems!

Cheers!

Frank