Perhaps the conversation on alternatives to Venice after flying into Venice could continue in Italy forum on FlyerTalk:
https://www.flyertalk.com/forum/italy-634/
This topic is closed so that the conversation that is not directly related to BA flights can be kept in one place, where it may be useful for other people considering similar options.
If BA do change the rerouting policy due to the water level in Venice, we invite the OP or anyone else to request to re-open the topic.
LTN Phobia
Moderator: BA forum