have got it working now by unticking static ip
Yes that shouldn't be ticked. IDNet provide static IP addresses by configuring their DHCP servers to always hand out the same address. It keeps things simple.
1. Reconfigure your firewall
In what sense? That's a pretty useless suggestion. A bit like 'eat more healthily' :-/
2. Get a reverse DNS record
Not sure why that's a recommendation but it's easy enough - just email IDNet support.
3. Use IPv6 as your default
That's down to your browser and/or operating system.