Photo is from Royal Opera’s 1991 production
https://www.bbc.co.uk/programmes/m0017ml3
In this R3 recording (5/2014, Barbican), Martyn Brabbins conducts the preferable original version; when Royal Opera revived Gawain the composer was required to make cuts to avoid overtime payments for the orchestra.
http://www.colinscolumn.com/martyn-brabbins-remembers-harrison-birtwistle/
What a stupendous opera Gawain is. A fantastic performance too, sustaining the long acts, both 90 minutes, with so much drama and excitement. Brabbins and Tomlinson talking about Birtwistle also made an impression, interesting to hear memories from those close to the composer.