DIN tape deck cable colours

Neil, the tails should show you the direction markers, unless they have worn off, of course.

Here's a picture of the current Naim Tape interconnect.  The earlier one looks similar but with nickel Deltrons in place of the gold plated Chord RCA plugs. Colours are Black/Red for input and Yellow/Blue for output.

Alas, Richard, I think the OP really needs to know which is left and which is right as well as which are record and which are play. 

I last had this problem in 2010.  I looked up the old thread it was "DIN/PHONO Tape lead connection"

What I came up with was :

                    IN (Rec)                      Out (play)

Left               BLACK                       YELLOW

Right             RED                           BLUE

The In/Out bit is what it says on the tape recorder, and produced the correct effect and correct channel with my Nakamichi CR7, although others suggested that I had it back to front.  The lead was a Chord Company one (the old matt red cable, not the Crimson one)

yes mine have nickel plugs but then they did come with a NAC32.5 so pretty old. Works a treat though.

Is it worth having the kit serviced I know my flat cap and NAC 32.5 have been regularly serviced. Not sure if the NAP250 ever has

Yes.  Before I reluctantly decided to sell my 135s, I had them serviced and the improvement was very obvious.  My old 52/52PS (serviced etc at same time) are still doing sterling service for my younger son-in-law.