Prior to and following D-Day, North Witham, AAF Station 479, was the home field for the Pathfinders of the IX Troop Carrier Command.This force flew specially equipt C-47 troop transports.The operations of this group have been my select area of study for nearly 23 years.
Written records of the Pathfinder operations are practically non-existant.
I do however, have the operational summary for Operation MARKET-GARDEN, the invasion of Holland (SEP44) which gives a summary of stations and organizations in England at that time.I find that the 29th ADG and the 16th DRS were component organizations at North Witham at that time. Under the heading of the 29th are also found: 16th Depot Repair Sqn. 96th Depot Supply Sqn. 1451st Ord MM Co. 918th Signal Repair Co. 1254th QM Truck Co. 321st Station Component Sqn.
As it was a field oriented toward troop transport it is most probable that your relative worked on C-47 type aircraft.
Here is a summary from a 'forgotten fields" interest page:
North Witham, Station 479: IX TCC: 29th and 85th ADG, with depot repair and supply squadrons, quartermaster truck company and supply platoon, Ornance Medium Maintenance Co., MP Co. and Station Complement Sq., pathfinder school of IX TCC (later to Cottesmore), hangars erected by US 833rd Eng. (Av.) Bn., handed to No. 4 Group, RAF Maintenance Command in 1945. Today forestry, runways visible from air, one hangar and former technical site used for light industry.
To get an overview of the area here is a site for an aerial photo.The field is on the right side of the screen---looks like a bow and arrow.Follow the prompts on the left side of the page to get down to a relatively close view.Also click on the map overlay button to better orient roads and buildings.