What is the purpose of a tamping spur?

There is one at Southampton Central oppo the NR p/way office I think. I saw it used a few months back for parking a tamper: never seen it used before in all the years I have been down here,

You can get a 6 car D stock in the siding (accessed from the bay road) at dagenham East - it's a scheduled rusty rail move that never happens after the evening peak

Are you thinking of Plaistow? That'd make more sense to me.

I can't remember the road number off hand, but the one accessed from 24 road at Parsons Green also springs to mind - and how about 33 road at Triangle sidings? Though IIRC, they're referred to as engineers sidings.

On the NR side at Upminster, there's a short siding off the bay road; there's often a Tamper parked there, so I assume that'd most likely be an official contender.

It was only a matter of time...