This extreme sweptback delta was built to test the Concorde wing at low speeds, sources say it had a biconv 6% airfoil, but I failed in finding data about it.
Did you see what Wikipedia had for it, and the book it came from?
Specifications (HP.115) Data from X-Planes and Prototypes: From Nazi Secret Weapons to the Warplanes of the Future [Winchester 2005, p. 134]
Length: 50 ft 4 in (15.33 m)
Wingspan: 20 ft (6.1 m)
Height: 12 ft 9 in (3.9 m)
Wing area: 432 ft² (40.1 m²)
Airfoil: Bicon 6%
Empty weight: 3,680 lb (1,670 kg)
Useful load: (Fuel) 1,175 lb (533 kg)
Loaded weight: 5,050 lb (2,291 kg)
Powerplant: 1 × Bristol Siddeley Viper BSV.9 turbojet, 1,900 lbf static (8.455 kN) Performance
Maximum speed: 248 mph (399 km/h)
Endurance: 40 minutes
This paper goes into calculations on biconvex airfoil as well, interesting reading https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930085007.pdf