As you specifically mention gifting, I have made several distributions to my family and on each occasion write to them confirming the date of the transfer and the amount and, in the certain knowledge that they will have lost these letters when the time comes, have attached signed copies to my will. As with much tax stuff, a lot relies on the openness and honesty of those left behind (will those valuable paintings still be on the wall when the tax man comes?!) but a point to watch out for is that the beneficiaries do not always understand the import of the information they may give. For the purpose of completing the IHT400 form, Executors will probably ask the family if they have received any lifetime gifts. As Executor to my bro-in-law's estate, I noted that my nieces had declared to the solicitors substantial amounts as taxable lifetime gifts, which I realised were not gifts from their father at all, but entitlements of a Trust of which their father happened to be a Trustee.