Cable Forum - cable modem

Hello this is my first post here and I really need help.

I have had random disconects between 6:00 pm and 11:00 pm every evening. The problem is not with my system of that I'm sure because even when I diconnect my PC it still does it. My modem restarts itself 2-30 times each evening but it's fine during the day. It happens like this every time. The internet goes down and when I look at the modem the power light remains constant but the sync light starts flashing, then the ready light goes off then starts to flash slowly then faster and then it comes back on. At which point my internet connection comes back online. It only goes down for around 30 secs but as an online gamer this kicks me from the server I'm on.

My location - eh54
I'm a former telewest customer.
Modem - AMBIT 256

So far I have had 3 engineers out and in this order this is what they have done.

1. Replaced conectors on line to house and swopped my old surfboard 4100 for the new modem.
2. Checked the connection from the box in my street to my house (said it was fine).
3. Came to my house and I explained what was happening and that it only happened in the evening so he said it was a network problem and left.
4. Phoned again because I'm still having the same problem (in fact it;s getting worse) so another "supervisor engineer" is coming Monday to look at it again.

Last night during one disconnect I took screen shots of my modem levels so I hope this will help.

http://www.regal.pwp.blueyonder.co.uk/11.jpg
http://www.regal.pwp.blueyonder.co.uk/12.jpg
http://www.regal.pwp.blueyonder.co.uk/13.jpg
http://www.regal.pwp.blueyonder.co.uk/14.jpg
http://www.regal.pwp.blueyonder.co.uk/log.jpg

Some history as well I'm not sure if it's relavent but 5 years ago my road was dug up and the cable was torn to pieces. It was repaired and I have no idea if the repair is still ok.

Its working fine at the moment and these are my settings

Cable Modem Upstream
Upstream Lock : Locked
Upstream Channel ID : 2
Upstream Frequency : 25800000 Hz
Upstream Modulation : QAM16
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 52.0 dBmV
Upstream Mini-Slot Size : 2

Downstream Lock : Locked
Downstream Channel Id : 6
Downstream Frequency : 331000000 Hz
Downstream Modulation : QAM256
Downstream Symbol Rate : 5360.537 Ksym/sec
Downstream Interleave Depth : taps32Increment4
Downstream Receive Power Level : 4.9 dBmV
Downstream SNR : 38.6 dB

The downstream power level constantly varies between 4.7 and 5.2 I don't know if this is normal so thought I'd better mention it.