Change IP now no vhost

First I need to say my server runs on a local network - can't afford hosting at the moment - for that reason I often have to change the shared IP address when my internet provider change the web facing IP on the router - this is also the reason my I can't upgrade to PRO

I've change the IP a few times but today I had a problem, I'm now getting "You don't have permission to access / on this server." on all my domains accept the base domain which works.

I've tried everything to resolve this, I don't run Mod security  so it's not that. I'm ran the permissions fix.

Anyone any ideas? this thing has been running for month fine before I made this change.

I don't why but I discovered that putting this in the htaccess file fixes the problem, don't have clue how changing the shared IP address would result in that but here it is;

Options +SymLinksIfOwnerMatch