Is the hand rail indoors or outside?

its indoors and runs up to third floor

If it's indoors and really is extraneous (e.g. let into a solid floor that doesn't have a damp proof membrane), then bonding seems sensible.- even if it is made "live" by fault (PEN or otherwise) everything else within reach should be at a similar potential, so the risks of a shock should be reduced rather than increased.

   - Andy.

It seems we are harking back t 15th Edition somehow?

Yes, there are situations where an internal balustrade in contact with the general mass of earth would require bonding ... and perhaps as an extension an external staircase, but I need to ask a very important question.

This is about the fact that it's an 'inspection'.

• What information is there about this balustrade?
• Is it 'internal' or on an upper floor of the premises?
• What design information is there from previous works (and why it was bonded)?
• Have there been any consultations with the EAWR duty holder?

In my view the hand rail should be bonded. The hand rail or balustrade is probably already somewhat connected to earth via potentially damp building fabric, there are many opportunities for such  fortuitous contact with a structure that is electrically continuous over several floors.

In the event of an open PEN there is the potential for a dangerous touch voltage between say a bonded metal pipe and the hand rail which is somewhat connected to true earth.

 Newfutile 

What exposed conductive parts can people touch whilst having a hand on the handrail, which is possibly an extraneous conductive part?

Good point, simultaneously accessible is often forgotten about.

Sparkingchip said:

What exposed conductive parts can people touch whilst having a hand on the handrail, which is possibly an extraneous conductive part?

No argument there but as far as I can see, if something is deemed an extraneous conducive part, the current edition of 7671 requires MPB to be in place irrespective of whether there are accessible exposed conductive parts or not. 
The 16th Edition made it clear in 413.02.04;

Or perhaps, there was no need for the current edition of 7671 to convey the common sense in Sparkingchip’s remark? 

far as I can see, if something is deemed an extraneous conducive part, the current edition of 7671 requires MPB to be in place irrespective of whether there are accessible exposed conductive parts or not. 

Which in these days of portable Class I appliances, not to mention extension leads, is probably no bad thing.

  - Andy.

“its indoors and runs up to third floor” describes the handrails in the housing association flats where used to work, the lighting installation on the stairs and landings in the communal areas were part of the installation supplying the external lighting in the car parks and on the paths in the communal garden area and bin stores, so although indoors formed part of the external installation.