Where are the rules that clients will use to determine your IR35 status?

[mudskipper]

If I go to the CEST and fill it in as if I was the client the 3rd or 4th question is regarding the right to substitution.
If I choose positively ( as per my agreed contract ) the tool immediately finishes with an IR35 does not apply message.
Why would the client then be concerned with any other measures, advisors etc..?

The wording of the question isn't helpful - "Yes - we have the right to reject a substitute for any reason, including if it would negatively impact the work" - what client in their right mind would say yes, we're happy to negatively impact the work.

[The Dogs Bollocks]

The wording of the question isn't helpful - "Yes - we have the right to reject a substitute for any reason, including if it would negatively impact the work" - what client in their right mind would say yes, we're happy to negatively impact the work.

There might be other issues that might lead to a client rejecting substitution even when it is included in the contract, e.g. national security

[gorses]

I will be taking this opportunity to educate the client now, or I will only extend up 'til Feb/Mar and then take a stand.

Yep me too. Albeit educating them to what they've already signed up to, engaging my LtdCo. not me. To be fair to them they do understand and agree to this point, they're just mystified as to what the fuss is all about and why my personal tax is their business.

To be honest I was surprised the CEST immediately finished after the substitution question, was expecting a deeper analysis.

[northernladuk]

Please please please read up and make sure you know what you are doing when you speak to your client. Get it wrong and you are going to do yourself and your client more damage than help. We've had some awful comments from people that should know more about IR35 and were going to speak to their clients and I know some people at my client were trying this via agencies and some of the stuff they said in office was scary.

If you aren't very well versed then it might be better you send them some links/literature and introduce them to a company that offers a service like QDOS to help them rather than trying to lead it from the front.