No 20142 Sir John Betjeman
There's a few that have them fitted, I can only see them on later photos, nothing (that I can find, anyway)
20164 /156 / 174 / 219 certainly had them.
There's a couple that seem to have a similar fitting on the other side soleplate, towards the front, but the photos are a bit grainy.
The Breedon No.3 (D8319/20219/20906) has a blanking plate where it used to be - and a blanking plate where the fire extinguisher pull was also.
I assume this was a local/overhaul modification that only happened to a few