So, after double-soft-proofing my images using Blurb's ICC profile (for the printer my images should be printed on), I feel that the colour is being washed out more than i'd like. To resolve this i've been working with a copy of the original PS file next to the original. The copy has soft-proof turned on, this then allows me to try and match up the colours with the original accordingly. Thankfully, the differences are not too drastic and generally only requires the contrast boosting up.
I am a little concerned that some images display areas of colour that are out of gamut (tones that wont be represented accurately in print), but after reading through a LOT of Blurb forum discussions, this shouldn't be too detrimental. I initially tried to bring out of gamut shades back in but it affects the whole image and seems a bit invasive. The general consensus with the Blurb community is that shades that are out, actually print fine.
At worst, out of gamut colours will appear duller than what I see on screen and it really only affects areas with a large amount of green. This could prove annoying with the example below. Areas that are out of gamut are greyed in.