There are several things to check.
1) Are you legitimately "in business"? I.e. do you run a business which provides a service to anyone who can afford it? If you're working exclusively for one company, then you clearly don't and are stuffed.
2) Does the contract with this company state that it's employing the services of your company or you exclusively by name? If the latter, you're stuffed.
3) Does the contract with this company contain a substitution clause? I.e. that you are able to supply anyone of equivalent skill without prior consultation. From what you've said, I doubt it does, in which case you're stuffed.
4) Are able to choose the hours you work?
5) Are you able to choose where you work?
6) Will you be reporting to a single manager?
7) Is there honestly any difference between your employment with this company and that of a permanent employee?
It sounds to me very much like you are are trying to get round paying PAYE and NIC. In which case, what you are doing is completely illegal. As has been previously mentioned, IR35 was set up precisely to catch this sort of tax evasion.