I think you need advice - probably from the fella who drew up the trust in the first place
If the trust deed allows you to sell then you dont need anyone's permission - but I think your children may notice anyway
from a site:
Tax treatment
The trustees are responsible for declaring and paying income tax and capital gains tax. The income received belongs to the life tenant and is taxed at their personal income tax rate.
For capital gains tax, the trust is taxed. The trust will have an annual allowance to offset against the gain.
If the life tenant lives in the trust property as their principal private residence and that property is sold, it is not subject to capital gains tax.
For inheritance tax purposes, the trust will be treated differently depending on whether it was established in your lifetime or by your Will.
If in your lifetime, inheritance tax may be due when:
On each ten year anniversary of the Trust
When assets are put into the trust
When assets are transferred out
oo-er strikes me you need professional advice !