When the firm went into administration in September 2023 there were 1,292 unsecured creditors with claims totalling £113m.
That figure was increased in a progress report from Grant Thornton in April to 1,375 claims totalling £256m.
The latest update filed at Companies House shows that total is now 1,391 claims worth £302.2m with suppliers and subcontractors unlikely to receive a penny for their unpaid bills.
Grant Thornton has been paid more than £5m for working out the administration so far with another £1.6m expected to be incurred in fees and expenses.