I have my mikrotik router plugged into my main router. The mikrotik has an IP address of 192.168.0.30 from my main router and also it's 192.168.88.1

I can access the webfig panel when connect to the WiFi on the mikrotik but when I am connected to the WiFi on my main router I cannot access the webfig panel using 192.168.0.30 is there anyway to change this?

Has your problem been resolved?

If not can you export the config of your MikroTik router that's on 192.168.0.30?

Has your problem been resolved?

If not can you export the config of your MikroTik router that's on 192.168.0.30?

No sorry it hasnt been resolved. 192.168.0.30 is given from my virgin media router

I think that the firewall rules in default settings of RouterOS drop new connections "from outside" / "coming to WAN port"

How can I enable then and also for the routeros to be able to see computers on my 192.168.0.* range?

I suppose your "main router" already has a firewall protecting you from internet attacks. If it's true, you can delete all your firewall rules in RouterOS (menu: IP -> Firewall) and try if your network works as expected. If not, reset your router to default/factory settings and start again

I suppose your "main router" already has a firewall protecting you from internet attacks. If it's true, you can delete all your firewall rules in RouterOS (menu: IP -> Firewall) and try if your network works as expected. If not, reset your router to default/factory settings and start again

Deleting all firewall rules works great! Is it safe to leave it like this as have port 1723 open?

I don't have enough information about your network to answer that, but RouterOS doesn't listen to port 1723 by default (you can see the ports and services in IP -> Services) so I GUESS your MikroTik device is safe.