"IR35 doesn’t apply if you work for a client through a Managed Service Company (MSC) or agency, for example an employment agency."
"Using an agency or MSC to provide a service to a client
There’s different legislation to follow if you provide services to an employer or end client through a third party agency or MSC.
You have to comply with agency legislation rather than IR35 if you provide services to an employer through a third party agency and technically, you’re not a direct employee of either.
If the agency is based outside the UK the client may be liable to operate PAYE and make the appropriate deductions, returns and payments of tax and National Insurance contributions instead.
You need to follow MSC legislation rather than IR35 if you provide your services to end clients through an intermediary company which is controlled and run by a third party service provider."
Sounds like the case?