Reading a previous comment I just cannot get my head around this Quote "most MP's are in deep with avoidance schemes which as I say are completely legal and are not intentionally set up to avoid tax "
Some if not most good schemes are for entirely genuine and important protections. If you just look at the tax system - Lord Clyde in 1929 stated that it is for the people to pay the least amount of tax that they are legally required and not accept that the government have the right to take the maximum that they can get hold of.
A simple and well used system - Directors/shareholders are not required to pay themselves a salary which could well be taxed at the highest rate along with both the employer and employee national insurance payments. Instead it is quite legal to only pay a dividend based on their shareholdings which attracts considerably less tax and no national insurance liability.
If you own two properties, one worth £500,000 and bought for £450,000 and the other £800,000 which was an inheritance. One of them will be liable to Capital Gains Tax if it was sold - which one would you want to protect? Obviously the one with the highest profit. You state that that one is your principal private residence and have the former treated as an investment. You decide which property to live in.
This no different to what MP's do when they own a couple of properties they decide which one they want to call their PPR. There is nothing stoppin you swapping that decision at any time if it suits.
Trusts especially Discretionary Trusts are a really good way of disposing of you capital legally.
As regards unintended effects. What is done to say protect or reduce a liability to Inheritance Tax (which is entirely a voluntary tax) may well have the added advantages of not having to pay for care fees or indeed it is possible that it may help to secure an extra or increased welfare benefit payment.
As regards taking a dividend instead of a salary may well be based on the reason of keeping the maximum remaining capital in the business for the future - why give it to the Treasury