[buckleb]

The engineer came around today and has fixed the problem.

It turns out that there is a splitter inside the white box that was quite old and was failing. He replaced it and all seems good again.

Downstream
1	323000000	2	38.9	256 qam	24
2	315000000	2.2	38.6	256 qam	23
3	307000000	2	38.6	256 qam	22
4	299000000	1.7	38.6	256 qam	21
5	291000000	1.2	38.9	256 qam	20
6	283000000	0.7	38.9	256 qam	19
7	275000000	0.9	38.6	256 qam	18
8	267000000	1.5	38.6	256 qam	17
9	259000000	1	38.9	256 qam	16
10	251000000	0.7	38.6	256 qam	15
11	243000000	0.7	38.6	256 qam	14
12	235000000	0.7	38.9	256 qam	13
13	227000000	0.4	38.6	256 qam	12
14	219000000	0.5	38.6	256 qam	11
15	211000000	0.5	38.6	256 qam	10
16	203000000	0.4	38.6	256 qam	9
17	195000000	0.5	38.6	256 qam	8
18	187000000	0.9	37.6	256 qam	7
19	179000000	0.7	37.6	256 qam	6
20	171000000	0.9	37.6	256 qam	5
21	163000000	0.9	38.6	256 qam	4
22	155000000	0.5	37.6	256 qam	3
23	147000000	0	37.3	256 qam	2
24	139000000	-0.4	37.3	256 qam	1

Upstream
2	39400000	ATDMA	45.8	16 qam	6400000	5120
1	46200000	ATDMA	45.8	16 qam	6400000	5120

Thanks for the advice guys.