Having missed Alwyn Mellor’s acclaimed performance as Isolde at Grange Park last month (a problem with her voice obliged her to hand over singing duties to Susan Bullock on the night I attended), I was pleased to find her back in full-throated form as Longborough’s Brünnhilde in Siegfried. The assured confidence in the role she showed last year in Die Walküre is again apparent, although of course we must wait well into Act III to hear her, as the heroine is wakened from her long sleep on the fire-girt Valkyrie rock by the fearless Siegfried (an impressive debut in the role by American tenor Daniel Brenna). The glorious, ecstatic duet, during which their mutual love is acknowledged and their union sealed with the Ring, was superbly handled.

The thunderous acclaim offered to them and the other singers at the end of this deeply satisfying production was intended as much, one felt, for the begetters of this amazingly ambitious project.

In two years’ time, when Longborough founder Martin Graham’s dream is fulfilled, we shall see the first Ring cycle ever performed in a privately-owned opera house (Bayreuth, of course, apart). This will be an apt celebration of the bicentenary of Wagner’s birth.

Crucial to the endeavour is the dedicated Wagnerian Anthony Negus who in Siegfried again conducted with masterly authority, encouraging magnificent work from players and singers. I hardly dare expect ever again to hear, for instance, the pastoral beauties of Siegfried’s encounter with the Woodbird (Allison Bell) conveyed so touchingly.

I remain unsure about the wisdom of director Alan Privett’s staging, which again requires us to peer into dark spaces bedecked with ropes and scaffolding (designer Kjell Torriset; lighting Guy Hoare).

The surtitle translation, meanwhile, continues to offer an occasionally jarring note, as when Siegfried tells Phillip Joll’s mighty Wotan to “shut your gob”. But these are minor faults in a production that offers many rich rewards, and especially in the vocal performances of Colin Judson’s superbly articulate Mime and Nicholas Folwell’s sensational Alberich.