[Sephiroth]

The engineer should be shot after being fired, IMO. You should complain at the highest level and provide his name.

Anything above 8 dBmv will distort your downstream signal abd you'll be constantly seeking retransmits - hence lower speeds. Your neighbour's prolly got a 15 dB attenuator on the other side of their wall.

It is possible, I suppose, that the engineer took his decision based on the knowledge that your neighbour's house is close to the street box and has high downstream power and so there is margin for him to do what he did. Is that right or am I well off the mark?

But consider this. Your wall box is shot to hell. Damp gets in and you start to corrode. A diode effect begins and before you know what, you've got RF ingress or impedance mismatch which can set up all sorts and affect the whole street - IMO..

What's more, if the neighbour didn't sign a wayleave, he's entitled to rip your connection out if he thinks his performance is suffering.

Then mice can get into your house, or ants at least .......

You have to complain at the highest level becasue otherwise you'll be bashing your head against a brick wall.