To be frank....
While 3rd class is better than no honours, it's not much more
than a consolation prize, really. You can still put (Hons) after
your degree, but you'll be severely outclassed by the much more
numerous 2nd and 1st classes when looking for a job.
If you really wanted honours, you should be aiming for 2nd
upper. 2nd lower at the very least.