UKH

Please see photo. Apologies for foot...but is there too much two space or what? Should I go a half size down (unfortunately shop does not have the next half size down in stock).

The outside of your big toe is at the extreme edge of the foot bed, and that’s without a sock on. Take a pair of the socks that your going to wear most often to the shop and try on together. At the end of the day only you can decide what comfortably fits your feet.

Looks a bit big for me.

I push my socked foot into the unlaced boot so the big toe touches the end of the boot. Then if I can get more than a finger between my heel and the heel of the boot, it’s too big and will give heel lift and blisters.

It’s a rule of finger not thumb

Thanks for replying. The width is not an issue and the boot has a great lacing system, almost like a climbing shoe and takes my large big toe bunion no problem. Wearing the boots clambering over coastal rocks and walking for a couple of hours was fine as was walking along lochsides but over rough trackless ground and ascending for a couple of hours gave my heel a hotspot. I measured the insole against my other (sole now worn) approach shoe and its slightly bigger / more space in the toe box. That made me think the problem lay with the toe space. In the shop I was told a tumb width was 'standard'.

That made me think the problem lay with the toe space. In the shop I was told a tumb width was 'standard'.

Which is more or  less correct. The problem is that there is no 'standard'. Every foot is different and every person's preference is different. One person wants a full thumb width, for the other a pinky width is enough. 

What kind of boot are we talking about? If it's a general hiking/trekking boot then I would be quite annoyed with a hotspot after a couple of hours. If it's a mountaineering boot and all you develop after a hotspot at the heel after a couple of hours of hiking in them then I wouldn't be all that surprised, especially if they are brand new. 

You may find this helpful:

When you put the boot on kick the heel against the ground so your heel moves to the very back of the boot. Then tie up the laces paying special attention to the mid section that holds the foot towards the back of the boot. 

Great advice.

I was told this for skiing boots and now do it for mountaineering boots as well. 

It makes a big difference