I type in
http://www.justforuphotography.co.uk/gallery/zp-core/setup.php
to get to the installation but get this error instead.

Fatal error: Call to undefined function mb_detect_encoding() in /home/justforu/public_html/gallery/zp-core/lib-gettext/gettext.inc on line 101

Please help what can i do.

This is a know bug in 1.1.6 related to the I18n feature. For more info:
http://www.zenphoto.org/support/topic.php?id=3020&replies=19#post-18009

Please try the nightly build, it's been corrected there.