It may be helpful to look at the judgement on which the practice note is based: https://webarchive.nationalarchives.gov.uk/20130604192647/https://www.justice.gov.uk/downloads/protecting-the-vulnerable/mca/orders-court-protection/gm-judgment.pdf
For what it’s worth I’ve discussed this with a colleague, and the conclusion we reach is that a strict interpretation does not allow for the previous year’s exemption to be added. However, I think a pragmatic approach is to consider what risk is involved. For example, if there is just one residuary beneficiary who would receive the gift in any case, or they are one of several residuary beneficiaries who agree to have the gift deducted from their share under the will, then it is difficult to see why anyone should object, other than HMRC. But I would doubt that HMRC would want to challenge the gift for the amounts involved. I hope this is of help.
Molesworths Bright Clegg