AHA! I can help, as i did all this last year. I'm dual, husband british. i have a great (and expensive) IFA dual qualified due to complex inheritance etc., so it's not a google answer
yes, if you keep the amount below the transfer threshold, you can easily back date it- the only "proof" of the gift as it is theoretical, is that you keep an excel spreadsheet or similar like you do to keep track of gifting and keep it near your will etc for the executors. The 2 things you need to have are a valuation of the house in question-- so that you know what percentage you are gifting each year. I just got an online valuation which lowballed it and printed it out. And secondly, you need to change the land register. You must SEVER any joint tenancy (if you have it) and have the property held as tenants in common. You register the % that each party owns. I owe 4%, husband the rest. You could get slicker and own the maximum under the inheritance threshold, but i didn't bother. (we've been married 33 years, no one is going anywhere and my 50% interest would be protected by UK divorce laws anyway)
