Virgin refusing to give a deadlock letter.

If it's been eight weeks since your complaint you don't need one https://www.virginmedia.com/help/complaints

Correct compensation rates https://www.ofcom.org.uk/phones-telecoms-and-internet/advice-for-consumers/costs-and-billing/automatic-compensation-need-know

Sadly, you describe a story that is often repeated on here regarding VM cable installations.

Any compensation due would be in line with the OFCOM auto compensation scheme

https://www.virginmedia.com/help/billing-and-payments/automatic-compensation

https://www.virginmedia.com/legal/fibre-optic-services-terms-conditions/automatic-compensation

VM routinely tries to dodge paying this (or paying the full amount) in the topics described on here.

VM has 30 days from the date when you were 'activated' to pay you what is due under the scheme. In all likelihood you will have to go to arbitration to get paid via this process

https://www.commsombudsman.org/our-process

If you have experienced property damage during the installation, I don't think this is covered by the ombudsman scheme AFAIK. You may need to use other forms of redress for that (such as small claims).

Include the failure to provide the deadlock letter as part of your complaint to the Ombudsman

Hi there PJL28 

Thank you so much for your post and welcome to the community forums, its great to have you here. 

I am so sorry that you have faced these issues with your complaint and I can fully understand your frustrations. I would be happy to take a closer look into this with you via a private message. 

I will pop you a PM across now, please keep an eye out for the envelope at the top of your screen alerting you to a new message.