Since switching to clipless pedals and Shimano RO87 shoes a couple of weeks ago, I've found that my toes get a lot colder - even in this lovely sunshine we've had recently! Wearing oversocks (Assos Spring/ Fall knitted) hasn't helped keep 'em warm much either. Maybe I just have cold feet, but is this a feature of wearing highly-ventilated road shoes? Is it OK to fit standard inner soles or does this totally block the ventilation?

I hear ya. Hands too. I can cover my face for cold rides, but hands and feet really annoy me and can make rides less enjoyable. I'd recommend getting some decent socks. I hear footwearetc has socks for a variety of uses. Haven't tried it yet. I'd also get some clip ins that have a little more wiggle room so you can put on thicker socks.