Is there an easy way to tell Idris and Telyn apart, especially if their legs are obscured?

Telyn

• Around 15% larger - easy to tell when they are positioned next to each other on the same focal plane
• Slightly darker head plumage
• Darker chest plumage
• Lighter coloured yellow eyes
• Has iris dots in both eyes
• (behaviour) Does approx 80% of the incubation; only Telyn food solicits
• Ringed - Blue 3J on right leg, metal (BTO) ring left leg

Telyn - Blue 3J ring, right leg

Idris

• Unringed
• Paler chest plumage - typical of males
• Has a whiter head (a bit like Dai Dot)
• Has 'eyebrows'! Brown plumage immediately above the eyes (white in Telyn)
• Stripe on the back of the head - straighter than Telyn's
• Hardly any iris dots
• Slightly darker, mustard coloured eyes
• (behaviour) More often seen on Monty Perch and lower perches
• (behaviour) Does all the fishing at the moment, so only Idris is seen with a live, uneaten fish
• Very pale underwings, hardly any brown plumage 

Idris has no leg rings