RichardWaiteSTFC

Re-opening this as WISH specifically requested it. Putting milestone 6.4 so doesn't get lost.

> @RichardWaiteSTFC - just tidying up the board for the current Mantid sprint. Is this piece of work complete now? Not yet, but I can work on it this sprint!

Code change looks good - I ran the script in #33917 and it executed in ~ 20 minutes. It might just be my setup so I will compare this to...

Found in manual testing #34353

>Do we know if this is a regression from previous versions? I can reproduce this in mantid v6.3 - so not a regression. Should we change to release 6.6?

Found in manual testing #34353

Written a script to parse PDCalibration parameters into a function string for fit benchmarking [ENGINX_PDCalib_demo_v2.txt](https://github.com/mantidproject/mantid/files/9744581/ENGINX_PDCalib_demo_v2.txt)

@thomashampson have core got any capacity to look into this next sprint? WISH have mentioned it again.

> I've just tried deleting `Vana_norm` and that is hanging so there is definitely some issue still there I've also had WISH scientists report the issue when deleting `Vana_norm`

@warunawickramasingha and I think this already works actually with the current track generation - but we want to make a plot/simulation to show this and add to the documentation.