Running cable from cooker control unit to cooker connection unit behind kitchen base units at floor level

Unfortunately the question is unclear (perhaps you could revise it making each of the points explicitly clear?). However it is permissible to install cables behind kitchen cupboards and in the void below at floor level. BS7671:2008 requires that cables are adequately supported and restrained, so some form of clips or other method (e.g. plastic trunking) should be used to enclose or secure the cables. You also need to consider possible vermin damage as cables in kitchen voids are prone to being chewed by mice etc.

There is no problem leaving the connection unit there, as long as the cable is connected correctly and the connection box is secure and there is no exposure to the connections. The cable and the connection unit should all be "mechanically protected" simply put it needs to be within a trunkin or within a wall caverty/under floor boards, and the connections made within the box wich makes up your connection unit, this is just to ensure there isn't damage to the cable in any way, also if you are not using the cooker anymore I would personally disconnect at the distribution board end aswell if it's on it's own circuit (I imagine it would be) Hope that helps Dan D H Electrical