Expenses that are within the civil service rates should be acceptable. The company should be able to stand over all amounts paid and the amounts paid should not be any more than would be reasonably expected so that the NE director is not out of pocket.
It is very important that adequate documentation is on file to show the basis of the payment broken down into mileage, overnight expenses etc and should be backed up with minutes showing attendance at the board meeting. Probably a good idea to have the director submit a signed claim form and have it approved by someone e.g. finance.
It would be important that it is not seen that the director is getting more than reimbursement of costs incurred as otherwise the excess could arguably be classed as director's fees and subject to PAYE/PRSI.