By Bradley Jolly Carole and Michael Middleton are unable to pay the £260,000 fees owed to the insolvency firm following the collapse of their business, it has been reported. Princess of Wales’ parents had operated Party Pieces but this fell into administration last year, owing creditors £2.6million. Interpath Advisory (IA), a city firm drafted in to handle the insolvency, is reportedly unable to cover all recoupment costs. The insolvency process involved longer hours than expected to meet statutory requirements and queries from creditors, it is believed. While the firm has received fees of £51…