Costa and neal - we did the same about 5 years ago. We have never worn markings on our tunics anyway so we have always relied on the helmet marking. Still works.
Out of PPE we manage quite well, the person in charge, if you wish to use that experession, is the one who allocates manages. Just like many other jobs.........how do you tell the manager in a factory, because they wear a different marked tie? No. How about the manager at Nissan, where they all wear the same? No markings there either.
As an aside when I was a newly promoted LFf I was on a visit, leading my crew, when a member of staff at the premises asked what the bar meant. A quick witted crew member said 'oh, that's to show he is a new member and needs supervision'. They believed it and I got tea, biscuits and sympathy from the office staff while they had to carry out the inspection, slight backfire on the Ff. So role markings needed except on the incident ground? No.