if a lump sum was granted on that retirement without any contribution being made, then unless that person on resumption ofF1. . . service, or within three months ofF1. . . marryingF2 or forming a civil partnership while again serving, refunds [F3 to the Consolidated Fund of the United Kingdom] by way of contribution one-half of the lump sum, no pension shall be granted to anyF1 widow, widowerF2, surviving civil partner or child of that person; and

any lump sum granted on that retirement, less any refund, shall be set off against any lump sum to be granted in respect ofF1 that person's service.