Reinforcement battles - to CTD or not to CTD

[Dayve]

Or to make things easier you could just withdraw whenever they attack you with reinforcements... The reinforcements will probably follow you and attack you alone, so fight those, then move forward again to attack the city... If they bring more reinforcements, do it all again... Obviously this isn't realistic because in reality sieges could last years... With this tactic you will have to assault the turn after you lay siege, otherwise you risk getting attacked with reinforcements and having to retreat and do it all again, but it has to be done...

Failing that, you'll just have to save and reload so that the script is de-activated, fight the battle and then activate the script again.