OK, here goes, I will try and reply to andy and wade's messages at the
same time...

I have an electrician coming in to do some work in my kitchen today, I
will ask him if he knows what type of earthing system I have. I live
in a flat, making it difficult to trace where the earth comes from. I
could get an electrician in to do the bathroom, but being a skint
student (electrical & mechanical engineering), and already having spent
a load of money on the suite etc, i wanted to see if it was possible to
do it myself (got a good deal on jacuzzi before you ask)

Both of you seem to disagree slightly on the size of RCD I would use.
According to other sites, 30mA makes it pretty unlikely that I would
ever be seriously hurt.

With reference to putting the RCD in the electrical cupboard, this is
something that a number of websites claim you can do. I suppose 30mA
would maybe be fine here also(?) because the equation L-N=0 still
stands irrespective of the load.

My heated flooring is from warmup.co.uk. which I got recommended by a
few people (good or bad I have bought it now ) . They do claim on
their website, after a bit of hunting that it can be used in bathrooms.

"The RCD could go on a wall as an RCD spur (see above) or could go at
the
origin of the circuit (ring or shower, whichever you use) near the
consumer unit".

When you say near the consumer unit, does that mean it can't go inside
the CU? What about if I use a rcbo?

The spur does get used at the moment for my fridge. The easiest option
sounds like using this. If I cut a new hole to house the RCD spur, is
there any reason why the fridge and jacuzzi cannot be connected to
this?

Thanks again for your patience

miguel