Exterior cable needs replacing

Hello

We had to call an engineer 3 weeks ago as our TV pictures were pixelating on a lot of channels. The engineer came and he was very good and checked the strength of signal and all cables going into the hub and they were fine,  then he said it could be the exterior cable.  He wasn't supposed to, but he went onto our flat roof (through a bedroom window) and found that the exterior cable and been chewed so he put in a connector and it fixed the issue - but he did say we would need a new cable.

We had another engineer called to install a new cable, but when he arrived he said he couldn't go out onto the roof and the other engineer should not have done this - because of insurance and Health & Safety rules - which I understand.  He said as everything was working - he would leave it but we should call again if we any more issues.  We have now had our hub go down twice in the last 2 days and the Virgin Status Checker ran checks,  and said that we should book an engineer - which we have done, however, how can it be fixed if the engineer can't go out onto the roof? Our Hive controller is connected to the internet so our hot water is currently not on due to us not having any internet, so I do need it fixed. We are happy to go out there and be instructed by the engineer - but is this the only way? Where do we stand on this? And how can we contact the engineer to warn them as I don't want an engineer to arrive and then they say they are not allowed out onto the roof to fix it .