<< Any suggestions would be much appreciated .. >>
You're telling us that you need a sill cock at deck level and that it may be
possible to tap into the supply pipes for the kitchen, right? So go ahead and
do it. If you don't feel confident about your skills, hire a qualified plumber.
Be more informative in talking to the tradesmen about what you want so they
don't waste time running hither and yon for parts. HTH