It means ten sites are now closed or about to close while eight are still operating.
The firm said it could not cover the costs of keeping them open, though it is ready to restart operations as soon as localised restrictions are lifted and viable demand for the individual sites returns.
To save more cash, head office and senior employees were asked to choose between a 25% pay cut or a share option scheme if they opt for a 40% reduction in salary.
Following discussions with landlords, rent was halved between August and December so the cashflow forecast remains unchanged.
Analysts at house broker Liberum expect these moves to result in £800,000 of savings while full-year net bank debt is estimated to come in at £27mln.
Shares were flat at 11.96p on Tuesday morning.