Thanks - this is at least logical advice! But poor that given you pay more for 1st class the facility to actually reserve it not being available makes no 'business sense'.....
I don't know if Inverness station has a barrier line (ie where you need to put your tickets through or on a scanner to get on the platform these days, or if you can just walk on to the platform). but as I indicated above the relevant carriages should arrive in bound at 10.29 so getting there around then or slightly before would be the time I would aim for
I think coaches A, B & C are the 170 train and coaches D & E will be the 158 train. The First Class seats are in coaches A and C.
given
@hexagon789 's info, no one else can have reserved the table in coach C, but someone
might have been able to do so in Coach A. So logic would say, get on the platform early, look for Coach C (there are doors near the 1st class seats), board and get seated at the table.
I predict coaches D& E to be nearest the concourse end of the platform as that train comes in earlier, from it's earlier journey from Dundee