iRule redirect from sports.test.co.uk/ioks/* to www.test.co.uk/ioks/*

You can use either strategy, but if there is a specific order you want them to be processed there is a consideration. If you added it to the existing rule you can definitely order the evaluation like you did above with an elseif. If you wanted a specific processing order with putting it in a new iRule you would want to use priority. https://devcentral.f5.com/wiki/iRules.priority.ashx. Also, if you want to retain the full URI you will have to do something like below. Below if the new iRule with a lower priority so it will be evaulated after the first iRules HTTP_REQUEST.

when HTTP_REQUEST priority 600 {
    if { [string tolower [HTTP::uri]] starts_with "/ioks/"}{
        HTTP::respond 301 noserver Location "https://www.test2.com[HTTP::uri]"
    }
}

You can use either strategy, but if there is a specific order you want them to be processed there is a consideration. If you added it to the existing rule you can definitely order the evaluation like you did above with an elseif. If you wanted a specific processing order with putting it in a new iRule you would want to use priority. https://devcentral.f5.com/wiki/iRules.priority.ashx. Also, if you want to retain the full URI you will have to do something like below. Below if the new iRule with a lower priority so it will be evaulated after the first iRules HTTP_REQUEST.

when HTTP_REQUEST priority 600 {
    if { [string tolower [HTTP::uri]] starts_with "/ioks/"}{
        HTTP::respond 301 noserver Location "https://www.test2.com[HTTP::uri]"
    }
}

The best solution is to create the new statement in the existing irule.

the Location header can contain only URI or all URL

• /ioks/ --> OK
• https://www.test2.co.uk/ioks/ --> OK

but not hostname without protocol :

• www.test2.co.uk/ioks/ --> WRONG

So the right code is (URI is added in the Location header as your question contains wildcard):

elseif {[HTTP::path] starts_with "/ioks/"} { 
    HTTP:: respond 301 Location "http://www.test2.co.uk[HTTP::uri]" 
    log local0. "This is iojs [HTTP::uri]"
}