Multiple Mixed Fund accounts or a single Mixed Fund account

My savings are in US Vanguard mutual funds (all non-reporting), and they are all Mixed Funds because part of my husband's income that was not taxed in the UK when he was a Remittance Basis taxpayer was invested in the funds. I need to sell and remit 3 of my 5 funds to enable us to stay here. My tax advisor isn't sure whether or not I can treat each of the funds as separate Mixed Fund accounts or whether I have to treat the entire Vanguard portfolio as a single Mixed Fund account.

Do you think the entire portfolio is a single account, or is each separate fund an account in its own right?

From the question, my understanding of the background is that the husband earned some income in the US at a time when he was a UK resident. He gifted the cash representing this income to his wife, and claimed the remittance basis for the relevant year.

His wife used the cash (perhaps along with other funds) to buy some US mutual funds. Therefore, as regards her husband, each of the purchased funds is considered a mixed fund. The mixed fund rules apply to “property”. Each of the funds is a separate property.

When some of the funds are sold and the proceeds remitted to the UK, the amounts of the gifted income attributed to each of the funds sold is deemed to be a remittance by the husband, despite the funds then belonging to his wife.

Separately the wife is taxable on the gains made on selling the investments. As the mutual funds are not UK reporting, the gains will be taxed as income under the Offshore Income Gains rules.

Thank you Dunedin for the very clear explanation.