Solved now...
I clicked through it, entered my database info then got this message:
Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock'
found a post on stack overflow about it here
which talked about replacing 'localhost' with the hostname of the machine where the SQL server resides, which I found somehow via my host control panel and it has worked.
I don't remember having to enter this on previous processwire installs with other hosts.
thanks guys
hey am I able to set this post as 'solved' – I have never worked out how to do that?
Alex
Alex's post in Apache mod_rewrite problem at install was marked as the answer