More recently Colin along with S del Pozo and D R Smith worked on the "Characterisation of a Novel Electron Beam Gun Design with a Radio Frequency Excited Plasma Cathode". The full report isn't free but a Industrial Member Report Summary – Key Findings for Industry is. The full report probably has the most recent information on the 10 kW gun.
I don't remember seeing who was working on the new beam deflection system but TWI has done work there. It's likely that they're part of the team working on it. There's a YouTube video on TWI Electron Beam Rapid Deflection. "The beam moves so fast that it may be timeshared between melt pools. Design and engineering of electron gun designs and equipment for beam generation, focusing and deflection are some of TWI's services." It sounds like multi-beam to me ;)
So based on a current build speed of .1 kg per hour an arc am system could produce about 520 kg per year assuming a 20 hour day (4 hr downtime/setup) and 5 days a week. This would be about 1146 lbs worth of parts.