The same company has booked me for another conference/seminar next year in a larger room. What suggestions do you have?

This one is simple.

For speaker you need this (to make it as close to mouth as possible just not before it to avoid breath noise):

It is small electret one, also larger dynamic ones exist (if you do not have small electric supply required for electret you can use it).

For audience you never use shotguns, just get good wireless dynamic microphone and ask to hold it close to their mouth

I suggest to look for newer digital systems, including Line 6 (as it has no level adjustments, very simple).

@spacewig There was no p.a. the room was small enough not to need it.The speaker was going through a Rode lavalier Rodelink system attached to his lapel wirelessly into a GH3 which was set up as a B Cam that my friend was operating on a tripod. I was filming on a handheld rig with a GH4 standing about 5 foot from the speaker recording with a Sennheiser MKE600 on phantom power going into Tascam DR 70D also mounted on the rig (that I synced up later to footage rather than feed back to the GH4). I monitored the Tascam through Sennheiser HD650 headphones and my friend monitored the GH3 feed through headphones ( I don't know the brand).

@LiquidAlpinist Thanks. I'll give the iZotope a go. What worked best for me was Adobe Audition noise reduction and a few sharp parametric eq cuts to clean the last artifacts without making the speaker too tinny.Ideally, I was looking of any methods of reducing the noise at source when you have noise problems in a room. I have a boom and a hypercardioid mic but I didn't bring them.

@Vitaliy_Kiselev Thanks - I haven't looked at headset mics before but I can see how that would help get closer to the source and reduce noise -I'll check those out. I was thinking of looking at the Rodelink The Newsshooter kit once it's available to keep things portable for hand held mics but the Line 6 looks like a much cheaper option for conferences/indoor.

@spacewig Yes that was the plan