I have an interview for a 3/5 year post doc position later in the week, I am SUPER prepared for the interview questions, presentation and technical knowledge surrounding the signalling pathways and techniques etc.

But the first part of the interview is a "60 minute written work-related task, which will include elements relating to the job description. You are not required to do any preparation for the work-related task".

I can only assume its being presented with a data heavy paper and critiquing it, how you would validate the work, or maybe writing the abstract, limitations of the study etc? Maybe a basic numeracy test for solutions and volumes and molar concentrations?!
I have no idea what to expect and am stressing my head off because its the only part of the interview i feel I cannot prepare for!
Does anyone have any experience of written tests for post doc interviews!
Any help would be much appreciated!

Congrats on getting interview! Two friends of mine had postdoc interviews where they had to analyse some data. Not sure if it would have been described as written or not (it was computer based - using specialised software). Try not to sweat about this. Part of what they'll be looking at is probably how you handle the uncertainty / stress of the situation. And certainly what will be the deciding factor on whether you get the job is you as a whole package, not a test performance. Good luck!