Yes, it was one of my fave shows as a kid and I still watch it with great fondness, I have the complete Region 2 DVD series and the radio play was very enjoyable and yes, it was a major pity that they decided to just end it with Cave of the Fairy Dragons and not animate Requiem! A few guys have tried to animate the episode down the past, though from watching the footage, I don't think I could get through the whole thing, which is a shame, as I have read the script and really would like someone to do a decent treatment!
As for my digital art, I just use the same program that most others do, Photoshop, though I have CS3 Extended, not the most current one, that you can only get as part of a subscription, which is a weird direction for them to take! But the way I did things here with this picture, is I used the Shapes tools for each of the colours and shading, mainly the Pen Tool, where I clicked an Anchor Point at points in the shape (always join back to the first point), then added bend Anchor Points to create the curves. The shade and shine was done the same way, though merely with black and white layers, then I changed the Blend mode and sometimes the Opacity to get the right effect: Shade layer 1 Blend Mode set to Overlay, 23% Opacity; Shade layer 2 left the Blend Mode as Normal, 40% Opacity; Shine layer Blend Mode set to Colour Dodge, 60% Opacity. I'm sure others will have different ways of going about things, but I find this to often be a quick method!