Re: No Moon
Yes, I have big stars that provide a little more light at night, and yes, the fact that the Moon stabilises the Earth's axial wobble is accounted for. Their climate changes far more rapidly and violently than ours, and it's the subtlest message of the whole series (I sound like a right prat now...)
The tides thing is interesting, because there would still be solar tides, though of course many times smaller (probably unnoticeable) than any lunar ones. Plate tectonics played a big part in evolution as well (the creation of shallow seas to help life step up onto land) so I think I have that covered.
Thank you all for your points, very useful.