In National Linen Service v. McGuinn, 5 Va. App. 265, 362 S.E.2d 187 (1987), the Court held that where the employer has stipulated to the compensability of the claim, has made payments to the employee for some significant period of time without filing a memorandum of agreement, and fails to contest the compensability of the injury, it is "reasonable to infer that the parties have reached an agreement as to the payment of compensation," and a de facto award will be recognized. McGuinn, 5 Va. App. at 269-70, 362 S.E.2d at 189.