Welcome to the forum, to answer your question's. You can get a rough idea with regard name by checking here https://canalplan.org.uk/boats/ but do not take it for gospel. Best to ring EA licensing themselves but be careful when I did that in 1999 they said my boat name would be "Vera 2" but when I got the licence it was for "Vera 4" so good job I did not paint "Vera 2" on the side. Surely the cheapest licence is just a Thames Licence on its own. Depends if you are going back on the canal's in the future in which case which is cheaper a Thames licence and an occasional CRT Visitor licence or the Gold licence, only you can decide that one as depends on your usage. We were moored on the Thames 1964 ish through to 2009 and it is fine if you know what you are doing.