modelman,
First comment = v good airmanship
Typical, wx looked great all day from the ground after that.Can't decide if I 'bottled it' or showed good airmanship
The haze you saw from the air could well have been mist / developing low-lying fog that, with the slant- angle you had (out of sun), just looked like haze. The cloud probably was cloud! Tis the weather that is normally pretty standard for a UK winter.
Perhaps it's time for IMC training
This probably would not have solved the problem for you. Look at the LIMITS that a the IMC ticket would have allowed you. I.E> you would not get to land in fog / mist. So would have had to turn back / divert anyhow.
Look how many CFIT incidents occur every autumn to spring in these situations caused by clots PRESSING ON REGARDLESS.
And for those that will disagree with me and claim that I'm too conservative - I agree. I fly fast pointy things for a job and GA (negligable navaids and no bang-seat for fun). I like the landings to = the take-offs

YOU DONE GOOD