The new building regs were drafted about 1985(?). The person drafting them tried to write 'you may not have a toilet pan in your kitchen' - . However the way he wrote it was unclear. The building regs are a statutory document, but they come with an interpretation that is not a statutory document. The interpretation interpreted the regs as saying 'you may not have a toilet in a room that opens off your kitchen. Ridiculous that the regs require interpreting by the same body that wrote them, but... Therefore in houses/extensions/alterations of this period, you will find an additional artificial lobby area built between the two. About 1995-2000, there was a new interpretation of the existing regs. The new interpretation states clearly that the regs had previously been misinterpreted, and that all that they prohibit is a toilet pan in the kitchen. Now, if you have a house in multiple occupation in Westminster, suddenly you fall under environmental health, not building control. EH in Westminster (I cannot comment on other parts of the country) have their own delightful regulations that ban you from having a toilet in a room off the kitchen... so you have to have a lobby again. To cut a long story short, I suggest you check with your local planning office.

Will just one side of the shower be open (ie shower in a corner with 2 walls) or 2 sides open? Do you have an image of the bathroom plan? Also, I would always consider adding a hand held shower head along with a rainfall shower for easier cleaning.

You have such a great space! It depends what kind of style you like, but the current modern trend for many of our projects is to use a full width slightly protruding headboard which is 600mm higher than the top of the matters height. Behind this a warm 3000K LED strip light is installed to light up the wall above with an indirect light. the picture below is a good precedent. www.dorarch.com

I'm so sorry it hasn't been delivered yet. The chimney breast sticks out into the room leaving alcoves either side. The bit sticking out is only 139.5cm wide and the mantelpiece will be on this but is 137cm wide, leaving only just over 1cm either side of the edge of the mantelpiece. I don't know if that makes sense!