I'm pretty sure I haven't seen any shepherds pie anywhere else! Not wanting to outstay my welcome, I head out again, and as I know the Skooma won't actually fetch 75 gold on the black market, I decide I had better steal some more things. I break into an armour shop and steal several helmets, gauntlets and shields, then head to Bravil to sell the stolen wares on to a fence.
My plan worked and I easily had enough to sell to advance with the missions. Skriva tells me that the Gray Fox is looking for a particular rare book, but that the thief who stole it hasn't been seen since he disappeared in Skingrad. I head there and learn that he was caught and imprisoned in the castle dungeons! I learn this from a beggar in Skingrad (beggars serve as the eyes and ears of the Thieves Guild. Hooray for stereotypes...).
The beggar glitch in Oblivion is well known (all the beggars have frail and decrepit 'common' accents when asking for money, but if you ask them about 'Rumours' then they switch to a completely different voice and become very well-spoken), but this instance is particularly hilarious: the beggar says the first half of the information in his normal beggar voice, then switches to the posh 'guard voice' for the entire second half:
This can't be a glitch at all, since those lines of text were only ever going to be said by a beggar, so there would have been no need to record them in a different voice. Therefore it must have been deliberate, so perhaps the other beggar 'glitches' aren't really glitches at all either!
For the record, I would probably prefer it if there were no actual voices, as that way they could add tons more dialogue options and you wouldn't actually lose anything from the game. At least in Oblivion your character doesn't speak, which something that completely ruined Fallout 4 for me. God, why did they make the character speak in Fallout 4?! What a dreadful, wrong-headed, immersion-destroying decision!
I manage to gain access to the castle dungeons by accepting a job delivering food to the prisoners. A great little touch is that after accepting the job, the castle guards start being horrible to me and say things like 'out of the way, slop drudge!'. It turns out the thief was killed by a vampire who feasts on the prisoners (I presume this is connected to the Count in some way) but his cellmate learned of the location of the book, and tells me after I free him.
All in all this was a great quest - it took some time to do, involved a bit of role-playing and some interesting conversations, and Castle Skingrad itself feels huge and realistic to explore.