You can set the default sender for an account with the use of this add-on:

https://addons.mozilla.org/en-us/thunderbird/addon/correct-identity/

http://chrisramsden.vfast.co.uk/3_How_to_install_Add-ons_in_Thunderbird.html

Tested and working here.

Hi thanks but this doesnt work on the forwarding of e mails in the sent folder..and you cannot set a preference for that

I'm interested in this because I've noticed that when forwarding mails from sent folder a "wrong" identity is taken. However, it seems to always select the default identity unless another identity was addressed in "To" of the original mail to be forwarded. Then it takes this one, which is really strange.

• Example 1:
  • From identity: name9 (not default identity)
  • To: somename1, somename2
  • Forward from sent: name1 (default identity) => From

• Example 2:
  • From identity: name9 (not default)
  • To: someotheridentity, somename2
  • Forward from sent: someotheridentity => From

Example 2 is obviously strange. TB should not look at the addressees (To). Example 1 might be ok, although I'd prefer if TB would always select the From identity of the original mail.

Only solution I see: if you feel this is important you're probably better off working with different TB accounts (within the same TB profile) rather than identities.

Did you adjust the add-on options so that the default account is selected for sending when the selected folder is in your daughter's account? Note that this will apply for replies or forwards, as well as new messages.

"Tested and working" still applies.

the sent folder is in my account,

It looks like this add-on is more suited to your needs:

https://addons.mozilla.org/en-US/thunderbird/addon/folder-account/

brilliant thanks