Door spindle not rotating far enough

[towser]

I replaced an old worn out door handle on inner porch door today. Kept the existing latch mechanism as its fine. Problem I have is that the new handle doesn't quite rotate the door spindle enough to make opening the door easy. The latch still sticks out by a few mm but enough to make it a problem.

Thought this would be a straightforward swap job.

Thinking the spindle may not have a tight enough fit in the new handle. That's a guess though. Any other thoughts / solutions??

Ta