All in one WP Security & Firewall ?

I have been having problems with website matildabickerton.co.uk and being locked out from admin. The latest event was a 403 notice which happened after I had enabled the captcha in the above security plugin. I tried renaming the plugin at public html but still a 403 notice. Left it for twenty four hours which did not change anything.

I asked the host (Falcoda – very helpful service) that if I deleted all the rules for All in One in the .htaccess file would that let me back in. They, helpfully, renamed the .htaccess file (obviously now defunct) and inserted a new basic WP .htaccess. I can now get back into admin. There are no rules at all in this new file, where as in the old file there were rules for All in One and some other plugins which I can not remember.

Obviously I am mainly concerned about security and do not want to be left open. Do I need to reinstall All in One and start again or should I follow this instruction at the top of admin:

“Would you like All In One WP Security & Firewall to re-insert the security rules in your .htaccess file which were cleared when you deactivated the plugin?”

Sorry it is a bit long winded but any help appreciated.

Paul