Gifts from IHT Allowances and from surplus income

My wife and I are retired and receive unequal amounts of pension income. We have a joint bank account so on the death of one party the balance will pass to the survivor. Can we use form 17 to comply and make sure the balance of our joint account is held equally for IHT purposes. Below is a quote that I have found online. "It would therefore be helpful for joint account holders who make uneven contributions to their account to put in place a declaration of trust to document the beneficial ownership of the funds in the account, if they want to ensure that these are held equally for IHT purposes. "

Hi,
The form 17 will not impact the actual pension income received as it is for interest and/or property income that is held in joint names that you then want to have a different beneficial interest other than 50/50.
Thank you.