The yellow ones are RN; Last year AIRFIX did a club members special edition which gave 1 bowser plus 1 Landie & trailer with 3 different sets of marking for each vehicle. I have never seen an RN version to be quite honest - I just followed the instructions in the kit !!! now that is something I don't normally do as I am bit nit picky and like to find a photo and finish a model to represent that actusl truck- but I did 2 yellow ones one for my son he is nearly 40 but hasn't advanced beyond aircraft LOL !!!! We bought 2 Airfix special editions so we could get extra RN markings and got the extra kits by buying dirt cheap JB models off e bay- you- are no doubt aware the Airfix model is from the JB moulds which the bought the rights to. Returning to your question I have loads of RN bowser pics but have never actually seen a yellow Tac version, just went with the flow as they say . .