Are Herald Caravans a manufacturer of caravans or a brand name of caravan? For instance like Venus is made by Lunar. Or maybe even both, once they were a manufacturer who was eventually bought by a larger company who then continued to use the name as a name of a range of caravans.
The third character on a CRIS registration would have no relevance as the name Explorer is related to a group of manufacturers combined under one umbrella. Coachman Caravans were once part of the Explorer Group back in the late 90's which my caravan was part of back then when it was built but on the CRIS number the third character is CM which relates to Coachman.
I know that the 3rd relates to the make of caravan and the 8th and 9th characters together for the company who manufactured it. Coachman is 4-&-CM where Elddis is
E-&-EL but though that Explorer is EX, I don't know what Explorer used for the third character.