Hi Arther, I also work in communications and am due to return to work in march. I am going to try for 4 days, work have already said they're not keen as its not fair on the team if I'm out for one day (potentially picking up workload) and I'd end up doing 5 days in 4 anyway.
My responses to these arguments are 1. I did 6 or even 7 days in 5 before I had DS, and I travelled a lot with work and was often out if the office anyway, only checking emails sporadically. The team managed.
I think the real reason they're not keen is that if they make the exception for me and allow me 4 days, then they'll get a queue of people lining up to put in their requests for fewer days. That is not my problem though.
Anyway, I'm going to suggest I use holiday to do 4 days a week for 12 weeks, and we assess whether it's working after that. If if is working then we make it a permenent arrangement, if not I will hand in my notice. There are plenty of other companies that are much more flexible.
I can't see they would have any grounds for saying its not working, as I know I can make it work.
Don't know if this is helpful or not but I'd be interested in how you get on since we're in similar lines of work. I'll keep you posted on my conversations too.