I got a faint positive result 2 days after period was due, now 14 days later I felt a trickle and when I went to toilet there was a small amount of red blood and a clot about 1.5 cms. Is this enough to assume an early misscarriage has occurred?

No, I wouldn't assume that from what you describe. You should see your doctor or midwife for a check. There can be several reasons for some early bleeding or spotting in pregnancy. Possible threatened miscarriage is just one of them.

I agree, it is not "proof" in and of itself. But I would be checked