Hi everyone thank you in Advance. I’ve done a fair few in inspection now and been as accurate and descriptive as possible . 
Question I have is if a Fd30 label is on the top of a door can this be identified as an Fd30’s, if all smoke seals are present ? Was there a date manufactures may have started used the “S” suffix on there labels . 

In short should I say it’s Fd30 with smoke protection and a Fd30’s door ?

It is the smoke seals only that give the smoke protection ? Correct ? 

I was always give the correct advice in terms of threshold gaps and correctly check fire and smoke seals are present . 

Appreciate and help. 

To my knowledge, all fire doors are manufactured as none smoke doors, it is the inclusion of a smoke seal (fin or brush) in the intumescent that makes it in S. There is no difference in the allowable gaps (except the threshold)

The door blanks are only ever labelled as FD30/60/90/120 and it's the completed door set, including the seals used, that determine if the 'S' suffix is applicable. The manufacturer's data should state which seals are OK for use in an 'S' scenario in line with the test data & certification.