There’s no built-in way to do this. This can only be done with a custom JavaScript (which you could automate via Airtable’s Automations), or with an external automation tool like Make.com, or manually.
Hey Aaron, as @ScottWorld said, you can run a script in an automation to delete a record once it’s no longer linked if you’re on a Pro plan. Here’s a working version of said script that you’ll need to customize:
let inputConfig = input.config()
let table = base.getTable('Table 2')
table.deleteRecordAsync(inputConfig.recordId)

If you’re not on a Pro plan, the best you could do is clear the fields I’m afraid:

I’ve set up both here for you to check out
Hey Aaron, as @ScottWorld said, you can run a script in an automation to delete a record once it’s no longer linked if you’re on a Pro plan. Here’s a working version of said script that you’ll need to customize:
let inputConfig = input.config()
let table = base.getTable('Table 2')
table.deleteRecordAsync(inputConfig.recordId)

If you’re not on a Pro plan, the best you could do is clear the fields I’m afraid:

I’ve set up both here for you to check out
Thank you for the clarification… Not going to lie… at this stage thats beyond my capabilities