Intergrated PIP/ESA/UC Assessment Trials in the N2 Area

I have a client who lives in the N2 area of London and has read that their area is part of a trial for integrated PIP/ESA/UC assessments and this has been causing delays in PIP claims being processed or information going missing.  She has also been advised that the number to contact the DWP is a different one to the normal PIP claim line.

Whilst their PIP claim was acknowledged in Mid December she has not heard anything since and is worried that she has been affected by the above.

The charity i work for is national and this is the first time i have come across this query.

I have found the following information on the benefits and work website:

https://www.benefitsandwork.co.uk/news/integrated-pip-esa-uc-assessment-trials-to-resume

I was just wondering whether anyone has any experience of this and could offer any advice or guidance please.

Many thanks.