Can't access mortgage funds

We have just closed the sale of a builders finish property. The mortgage includes €35k to complete/renovate/furnish the house, with funds being made available as the work is completed. However, all our money went into the deposit so we can't get work started. Any advice on how we can get around this? Will tradesmen issue invoices after the work is done and wait for their payment until such time as the bank releases the funding to us?