Floor to wall tiling - Tile Advice

[serval]

Going to be tiling a small cloak room floor and a wall plus boxed in cistern/ pipe work.

Ive tiled plenty of walls before but this will be my first attempt at doing the floor.
Im assuming that do the floor first and then overlap the wall tiles on top of the floor tiles?
A few other questions you guys might be able to help with.

The bathroom gets quite cold in winter as its on an external wall. Is there anything i can put down to try and insulate the tiles from being vert cold?

What sort of gap do you need to leave between the floor tiles and the walls

Also do you use grout at the joint between floor and wall tile or some sort of flexible sealant.

 

[WetSaw]

UFH will stop the tiles feeling cold!
Some people tile the walls first leaving out the bottom row, then the floor and finally cut in the bottom row of wall tiles. I usually tile the floor first then do the walls. 2mm gap between wall and floor siliconed.