What does the sign "Caution your blast" mean?
I'm fairly sure that sign is beside taxiway C*, and as you can see from the aerodrome chart it is right next to the main apron. Aircraft holding in this position have the main apron directly behind them.



The sign is instructing pilots to use the minimum thrust necessary to move off from that position, as there could be personnel, vehicles etc on the apron. As this is a bit of a mouthful "Caution your blast" is used.

This is further backed up by the aerodrome textual data which states:


  Pilots are requested to use minimum power when manoeuvring on and off parking stands and when entering the runway.
  The use of minimum power is particularly emphasised when holding at the the entry points to the runway and when
  entering the runway.


The other hold points around the apron seem to have a similar problem Taxiway B has the same sign. Perhaps the others do too.


(Image source: https://www.airlinequality.com/review-pages/gallery-airline-reviews/)



* This was based on personal memory of seeing this exact sign, and of being aware at which hold point we were at. I went and checked using google earth/street view. There is a good view from the terminal however the sign itself is obscured by an aircraft. However you can clearly see the building opposite from the original picture, and so the position for Taxiway C lines up.