I have an ecommerce site running that submits customer payments using SagePay's Form integration. I get the instant payment notification and it's been working fine for a couple of years.
I'd like to know if I can retrieve the Third Man fraud check results without having to view MySagePay and manually look?
You can do this via Sage Pay's Adming & Reporting API, its a different API but very easy to integrate with.
You can find the documentation here