// Because you can be dismissed for almost any reason (barring things like race) within the first two years//
the exceptions are those which are statutorily automatically unfair - race, pregnancy, doing union work spring to mind.[
https://www.gov.uk/dismiss-staff/unfair-dismissals ]
however did they pay you the notice period - or is there something in the contract that says they dont need to ?
also - who is the employer ? the company or the agency ?
and finally there is no claim for the manner in which you have been dismissed but only for the dismissal itself .
I agree that your only action would be wrongful dismissal for breach of contract, and for that you need to read the contract - remember we dont know what the main clauses are
... I think you have most of the answers to be honest
it is just answers you dont like much ....