Ruling question from Krakow

My regular junior partner and I played a Polish Grand Prix in Krakow this weekend, a great practicing opportunity in a beautiful town. The scoring was matchpoints without screens in use.

Halfway through the first session, two familiar guys who we 've seen at a couple of international youth events sit down at our table.

West
KQ853
A985
Q7
K3
North
A107
63
108
A107652
East
J64
K7
AK9654
QJ
South
92
QJ1042
J32
984
W
N
E
S

P
1
P
2
P
2
P
3
P
4
P
4
P
4
P
4N
P
5
P
5
P
6
P
6
P
P
P
D
1
6 West
NS: 0 EW: 0
10
A
2
7
2
0
1
4
2
K
A
1
1
1
8
4
3
Q
0
1
2
3

To clarify: A hesitation agreed upon by all players occurred before bidding 5. 6 was explained as "probably club void" by East when North asked before the lead. Note that West holds the Q.

The explanation of all artificial bids were as given (mouse over the bid). After North played back another diamond, the contract made. When the director was called North stated that he played back a diamond in case West had 5440 and South could ruff it.

The director polled eight players on what they would play after winning the ace of spades. All of them would have attempted to cash the ace of clubs, at least some of them stating things like "If you want more tricks, you can only play the ace of clubs".

Based on this poll the director ruled to let the result stand. He elaborated further that he deemed it to be impossible that West had 5440 after the given auction. Additionally, he brought up the point that West might have taken 3 as a splinter. 3 wasn't alerted though and as far as I know neither East nor West claimed to have had a misunderstanding there. Update: West explained that there was a bidding mix-up - see comments - and that he wasn't sure of the meaning of 3, believed RKCB to be on heart basis and 6 as reply to the king ask.

Was the ruling correct and if not, how would you rule?

Result stands
5 =
6 -1