Hi, I'm going to install a Devi Mat underfloor heating system and need something cleared up. Looking at the installation instructions, it states that you need a box 30cm up from teh floor with a blanking plate on however I can not make out why this is necessary as it only seems to have the cold tail to teh programmer and floor sensor down running through it rather than any connections. Is this right or am I missing something off the picture? So is this box and blanking plate necessary? Thanks