oh lord - and i know that place so well - although mainly from dreams now - i haven't been there in person since I learned to smoke.
do you know this?:
http://www.indigogroup.co.uk/edge/Toothill.htm
I live near 'Tothill' Fields now - thought to be an ancient sacred hill adjacent to the springs and the lost Westbourne and Tyburn rivers
But the whole little landscape around Halliwell is strange - the steep sided valley around temple lane and the lake at the bottom and the wood at the bottom of harpers lane. did you see the holywell?