Yes, the Ceriatone "British Style" 18 watt is the Marshall 1974 circuit that was "borrowed” from the Watkins (WEM) Dominator circuit much like the JTM45 circuit was "borrowed" from the Fender Bassman. Pretty cool how the history of the old amps worked out.
      Anyways, here's a rundown of the different circuits:
18 watt - the "standard" circuit - 1 normal channel with a12ax7 pre-amp, 1 tremolo channel.
18 watt TMB - the same normal channel as above but the tremolo channel is replaced with a non-tremolo full tone stack channel hence TMB for Treble, Mid & Bass controls.
18 watt TMB EF86 - goes one step further and replaces the normal 12ax7 pre-amp channel with an EF86 tube pre-amp very similar to the very early Vox AC15.
   If you're serious about building an 18 watt amp I highly recommend signing up here: http://www.18watt.com/   The guys on there are a treasure trove of info specific to the 18 watters. Hope this helps and good luck!