On the roundabout I mentioned I find that signalling right causes confusion. Other drivers seem to expect you to go into the Marks and Sparks car park.
Multimap picture here. Approaching from the east your first exit is a left at about 10 o'clock, the second is a right at about 2 o'clock which some treat as a straight on and others as a right, and the the third is a right into the car park at about 4 o'clock. I've found fairly consistently that the best way through this roundabout when taking the 2nd exit is to use the right hand lane with no signals and pay attention to what the car on the left is doing if there is one, and signal left once I'm level with the 1st exit. As I said before, if the car on my left is going for the 2nd exit as well I have the same options of brake or cane it (rather not) as they have, but also the third option of go around. So far so good, and still not had to do a go around yet, though I've had a couple of V signs and angry looks from drivers who haven't realised a crap layout has put both of us into a confusing situation.
The whole thing could be easily and cheaply solved with a few tins of paint. I use
this roundabout occasionally, which presents a similar situation for drivers approaching from the south. Sometime last year it got an arrow in the left hand lane indicating that it's for going left and 'right a bit'

, and another indicating the right hand lane was only for traffic going 'even more right', and some nice new matching road signs so drivers know the score in advance. Personally I think it would be more intuituve to have done it the other way round, but it really doesn't matter as long as they make it clear where to go for which exits.