JB
It's in the Alphabetic listing right at the top -
Ask the nice lady who answers politely for the Loans dept., explaining that "it isn't cheaper using her shiny cheap rate number" and she will graciously put you through to the Loans dept.
Been there, done it    Hope it helps.

I also found another number yesterday while searching on Google for the Halifax Mortgages dept. - 01422 333333, but when I tried it, they've moved it to an 0870 number.
So as a shareholder, I'm going to have a moan to customer services about it !!

333333 used to be a switchboard that out of hours went through to the telephone banking

but as you said it no longer works