Hello all, thanks for the replies

Right - I don't think its any sort of CREATURE because the noise is now
pretty much constant AND It is only audible from my room and not any of the
others around

I am feeling then that it must he something in the attic moving around or
most likely the plumbing or something...the odd thing is when I went up
there (stuck my head in) i couldnt hear the sound - partly because if was
prob drown out by all the other nosie of the roads etc)