I have had a look at a few other Annual Reports for a steer as...

I have had a look at a few other Annual Reports for a steer as to what “Likely Developments and expect results on operations - Information on likely developments in the operations of the Group and the expected results of operations have not been included in this report because the Directors believe it would be likely to result in unreasonable prejudice to the Group.” might mean.

In 2020 report there is a similar heading

"Future Developments, Prospects and Business Strategies - The above results formed the basis of discussions on development strategies which need to be undertaken over the next six months to put the Company in a position to potentially deliver a megabit chip and/or a corporate
transaction during 2021...."

This could imply this is to do with future activities of the company - it could pertain to sale discussions with prospective buyers / sale strategy and discussions held at IMEC - or perhaps just what the Board new prior to the IMEC meeting, noting this was probably auditors at the time they were at IMEC. By publishing this information it could prejudice those ongoing discussions.