Thanks for the welcome!
As you say as the Reading works have been known about for months, there isn't really a good excuse. When an unexpected incident occurs, then it is more understandable that correct information is more difficult to get out as events unfold.
I think the thing I find most annoying about this issue is that North Camp is staffed some of the day and someone did actually produce a hand written notice but managed to get the information so wrong.
Whilst on the subject, would there be a reason why the final stopping train of the day (23.14 from Guildford) was not operated throughout this week, or the subsequent semi-fast, altered to serve all stations? Coupled with the lack of correct information, I suspect there were a plenty of folk caught out my this and stranded at Guildford late in the evening.