After his long journey and spending the night in a railway truck in Aire-sur-la-Lys, Greg finally made it in the morning to his squadron – No. 42 Squadron RAF, Major H. J. F. Hunter, M.C., commanding – at Rely Aerodrome. He had a first, short flight with the squadron that afternoon.
Diary

Monday June 3rd 1918. Phoned up to 42 Squadron for tender. Managed to find an Hotel with someone in, where we had breakfast. Arrived Squadron (at Rely, nr Estrée Blanche, west of Merville) about 9.30am. Posted to B flight. (Merville – midway between Ypres & Arras.) [Side note] Squadron about midway between Ypres & Arras. Front includes Eastern edge of Forest of Nieppe & down to where the line cuts the La Bassée canal north of Béthune.
Log Book

Date: 3.6.18 Hour: 1.30 Machine type: RE8 No.: - Passenger: Sandbag flight Time: 10 min Height: 1500 Course: Aerodrome Remarks: Good landing
Rely Aerodrome
So began Greg’s time at Rely, where he was to spend several months. Rely is a small village set amongst farmland on the gently rising ground to the west and south of the Lys. It is about 31 miles (50 km) WSW of Lille. If the name seems familiar to British travellers to France today, it is probably because the Aire de Rely is the first eastbound service area on the A26 autoroute (L’Autoroute des Anglais) from Calais.

The First World War aerodrome at Rely was at 50°34’44” N 2°21’4″E (hat-tip to Anciens Aerodromes) , which places it on the Rue de Liettres, NW of the village centre just on the 100 m contour line. The site looks like this in Google Street View today:
RE8 E102
As it happens, today was the day that the Squadron’s daily orders recorded that the RE8 aircraft with the serial number E102, which was to be allocated to Greg the following day, was officially transferred to the strength of the squadron:

E102 had come from No 1 Aero Supply Depot. Following the Spring Offensives on 15th April No 1 ASD and its repair section moved from St Omer to Marquise, 8 miles (13 km) NE of Boulogne – http://1914-1918.invisionzone.com/forums/topic/121124-northern-area-repair-depot/.
The Front Line
The sector of the front line on which 42 Sqn was working ran, as Greg notes, from the east of the Nieppe Forest (just west of Merville) to the La Bassée canal near Béthune:

Most of the action that Greg saw would be in the north of this sector, near Merville.
Sandbag Flight
As Greg had no observer or passenger with him on his first short flight, he had to carry sandbags to ensure that the aeroplane was properly balanced, as explained here, under the heading “Crew”:
So now he was ready for whatever the next day would bring.
Header image: site of First World War Rely Airfield, from Google Street View.