Do I have to go and manually remove or delete all of this data before deleting to the pipeline or is there a way to ‘force delete’ the pipleine and all the data?
You need to make sure the pipeline is empty before you can delete it. This can be easily done by bulk deleting all deals in a pipeline: Delete CRM records
Navigate to the deal index page, switch to the list view, make sure the right pipeline is selected, select all deals, and delete them.
After doing this, you can delete the pipeline itself.