Hi, I am installing a new thermostatic shower and was planning to run the pipe from the valve, up through the loft, then down into a stud wall to the shower head. Just discovered its near enough impossible to run pipe into the loft. Will there be a problem running the pipe back down from the valve, under the bathroom floor and up into stud wall? Its only a slightly longer run but will it affect pressure or performance? (as you can tell I'm new to this game ) Thanks for any advice.