I see this as a one-off issue that needs to be dealt with as such. I know the events that led to the clash of dates and I can tell you (its up to you whether you believe me) that there was no malice involved, only a shocking lack of communication between both leagues, bad luck, and the total lack of compromise of at least one of the venue's involved.
That said, it should not happen again (except deliberately).
If it is not going to happen again, and if you believe the above, which I do, then it seems the ONLY reasonable thing to do is to allow an average score, or allow a disposable score. I do not feel it is in the leagues or the teams best interest to have substandard substitute teams in the first event. It makes no sense to me, excepting the format complications.
Alternatively, the games could be made up over the rest of the season as 'extra's'. In a league format there is ample precedent for this.
I feel for Pete and Magued. In todays climate the pressure is on teams to deliver increased return to sponsors. Substandard results are to be avoided more than ever, particularly in the first event of the season. It is an impossible situation that requires compromise to be made. In the bigger picture it IS important to do the right thing. Reputations take years to earn and moments to lose.
Pete, I don't know if I can help, and it seems unlikely given the personnel involved, but if you think I can, let me know.