Working for 3rd Party despite restriction clause

[thunderlizard]

15.1 The Consultancy shall not...for a period of 6 months following the termination of the Consultancy Services supply its services...to any Client for whom it has carried out Consultancy Services at any time during the previous 6 months.

What! That means you've got to basically dump all your retained clients for 6 months, however long you've had them. Completely ridiculous. Ignore it.

[centurian]

There are no IR35 implications, unless they have a different contract for opted in. And if you were introduced to the client before opting out, you're opted in regardless.

Doesn't have to be a different contract.

Some contracts are worded such that the substitution clause is only valid if you opted out.

No substitution = slap bang in IR35