Intermittent Fault on Navigation and Radio

[steamship]

Wondering if anyone can shed any light on an intermittent fault that pops up now and then when I do a scan. Just did one this morning (for another question) and am getting the following faults:

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Address 37: Navigation Labels: 4B0-035-192-RNSD-37.lbl
Part No: 4D0 035 192 N
Component: RNS 4.1 H05 BNO 0140
VCID: 2A511C71D6E4089

1 Fault Found:
01317 - Control Module in Instrument Cluster (J285)
49-10 - No Communications - Intermittent

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Address 56: Radio Labels: 4B0-035-192-RNSD-56.lbl
Part No: 4D0 035 192 N
Component: Radio BNO 0001
Coding: 00205
Shop #: WSC 02314
VCID: 2A511C71D6E4089

1 Fault Found:
01317 - Control Module in Instrument Cluster (J285)
49-10 - No Communications - Intermittent
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As I say, it's only intermittent, and doesn't appear to have any effect that I can see. The RNS-D unit plays CDs, the radio works, I have a reversing camera plugged in via the old analogue TV tuner and the sat-nav works. When in use, it displays the CD and track number on the DIS, or the radio station.

I do have some issues with the instrument cluster, which may or may not be related. The fuel consumption figures are screwed and always show an average of 200mpg and the range is way out (around 200mile when low fuel comes on, and around 1200 when tank full). I also have a bit of dot crawl in the top of the DIS. It starts around the very top line of pixels, and the longer the journey, the further it seems to bleed in. The other issue is that the instrument lights (with car lights off) are dodgy. The needles are lit permanently, but sometimes the instrument lighting goes off, almost like a loose connection. When car lights are on, instrument lights are fine.

Q1. Could the lighting issue be a dodgy bulb?

Q2. Is there anything else that the RNS-D should be doing with the DIS that I haven't seen, and would a replacement cluster resolve it?