This morning I tried various Verified and Unverified geographic numbers listed for HMRC's Self Assessment Helpline.
The only one I could find that still works fine and gets you through to the normal front end IVR system, then a human operator (after a wait of several minutes) and then a technical expert (if you need one) was 0161 931 9070 listed in the Unverified section as a geographic alternative for various different HMRC 0845 helplines.
All the other Self Assessment Helpline entries such as 023 9270 3003, 01236 783253, 0191 5411010 or 023 9240 1194 either no longer work (you get a message telling you to call an 0845 number instead) or they only get you through to an office that is not the actual Self Assessment Helpline. For instance the Cumbernauld 01236 783253 number is only a Collection Office for Self Assessment tax but not a Helpline that can answer queries on completing your tax return (they also deny they can transfer you to the Self Assessment helpline). Cumbernauld staff also insisted on lieing, till they were absolutely blue in the face (at both front line adviser and then supervisor level) that their 0845 numbers were definitely "local rate" and that I was wrong to claim they were not.
So it seems a fair bit of updating of the Self Assessment listings for HMRC is now in order.