: Many thanks! :)

: So, is the 'T Swiss Made T' not seen before?

That's right but it's not been seen as it's not correct for the model - tritium had been dropped from the first generation Carrera at this point and wasn't used on second generation watches; the "Chronomatic" dialled watches of Carrera, Autavia and Monaco, which are the earliest batch, all just say "Swiss". I don't know what they were using for reference either, because the first gen Carreras with one exception all just say "Swiss" too, with a T over the top if they use tritium. The exception is the Carrera 12 Dato, which for some reason does say "Swiss Made" rather than just Swiss but in that case the T is over the 12-hour register:

: Looking at the watch, close up, it's very fine work.

Yes, it's well done but there are a few telltales of refinishing - "A"s have pointed rather than flattened tops, Heuer shield is a fraction too narrow, the "C" and "A" of Carrera should be marginally bigger. None of these are visible to anything but a studied expert glance though, the first thing I noticed was the Swiss made text.

: I knew the case had been cleaned.

: I'll get the serial now... 1 sec.....

: :)

Yep, a serial of 150xxx is about where I'd expect this to be, which does indeed make it a 69/70 watch. The earliest 1153s are 147xxx, typically with the Chronomatic dial.