This was a bit part of the case for MIL. She was very vain and attention seeking, and having a smart salesman turn up at her small bungalow and tell her how special she was, and what complex arrangements were needed, she would have been sold. When she described what she had done we said, "Are you sure, it doesn't sound quite right?", but she insisted. We asked FIL and he said he had no idea what was being done, but she sulked if he questioned it. We all backed off.
MIL was nowhere near the IHT limits, but the inheritance planning company were more that happy to review, redraft and charge to manage it every year for 15 years.
When MIL died and we got to see it, it was nothing like what she had described. There would of been no protection from her imagined risks and wasn't even implemented to be legal or effective. Effectively she'd payed for nothing.
At first the inheritance management company wouldn't release anything to us (the executors) until we had a full financial consultation with them to asses how much money we had and how we should move our assets into the trust they wanted to create. Simply put, they are vultures preying on the vulnerable to line their own pockets. Luckily their product is so full of holes, with effort we can un-pick it, but this is taking alot of effort ( 3 years and counting)
Unless you are the Duke of Westminster, even for people living in the south with a big house, there is little to no point in any of this, apart to line the pockets of the planning industry. While the Governor estate may be an inter-generational asset, the "27a Average Road, Average Town, Wealth Trust" will be gone and forgotten is 15 years.
Give it to who you want it to go to before you die, and at least see the joy it creates. Give any left to who you want to in your will, they can do anything they want with it. If want to or you think you can control the living from beyond the grave, go and have a long look at a cemetery.
I have sympathy for OP, it sounds the same as us, and is a huge amount of wasted effort to appease the vanity of someone dead