Re assessment ?

I’ve been in the ESA support group for the last 20 years with my last re assessment in March 2013.

Received an ESA 50 form in the post not in the usual brown envelope but a white one straight from the Health Assessment Advisory Service , London. My benefit office is usually Basildon ( Essex) .

Any idea why it’s cone straight from the assessment service and not the DWP as such ?

Thank you

Re my previous post wanted to add I receive contributory ESA ( support group ) not income related