In reply to Aled Williams:
I don't think I've got too much else to add, as the other suggestions are so good. Grand Alliance is amazing and fits the criteria perfectly. Whilst I'm aware it's not E4, Prana - which is just next to it - is pretty punchy at E3, hence good training for getting pumped!
Tumble and Holocaust are a perfect partnership, as they're both immaculate, but both very different. The former is sustained, while the latter is cruxy. The only thing I'd say about Tumble is that the gear is quite fiddly and requires a bit of thinking to get in. It is safe, but you have to work to make it safe (if that makes sense).
I personally found One Step Beyond and Bitter Oasis pretty straightforward, but neither are what I'd describe as conventionally 'safe', but are good to get on when you're feeling confident. I would have said the same for Shadowfax, but having had a quick scan of the logbooks it seems that most people found that quite hard for the grade, so maybe I was going well back when I did it!!
Have fun with whichever you do end up on!