Was tax paid in the United States? If tax was paid in the United States, then there is no tax to pay on bringing the income into the UK.
Worry do you mention that the elder daughter is now entitled to full payment of the remainder of her share of the trust, you don’t mention the younger daughter?
How old is the younger daughter? Is she entitled to the trust fund at aged 40?
If both daughters agree, then under the ruling in Saunders v Vautier (Google will give you plenty of reading) the trust can be brought to an end and they can have the trust fund divided between them. The trustee doesn’t have to agree.
Can I clarify anything for you?
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