Sorry about yet another thread about ankle boots 
I've worked out what I'm looking for now - I like the heel to be the same as the boot, and I want a close fitting on the ankle so I can wear them with skirts and tights.
I've found these two options:
www.boden.co.uk/en-gb/womens-shoes-boots/boots/a0033-blk/womens-black-henley-ankle-boots
and:
www.danielfootwear.com/women-c2/louvar-black-suede-chelsea-boots-p90315
And what colour would you go for? I mainly wear black tights so black would be the most versatile option but maybe a bit boring?