Okay, I think I've got it:

Unit Trusts are pooled investments under trust deeds. They have

A manager, who manages the fund inc. setting price of units, buying and selling them.
Trustees, who provide investor protection and management checks.
Investors, who buy the units.

The offer price is the price investors buy units at from the manager.
The bid price is the price the manager buys units back from the investors.
The cancellation price is the minimum bid price.

The bid offer spread is normally around 5-6%.

Income is paid net of 10% tax which is not reclaimable for non taxpayers. Higher rate taxpayers owe an extra 22.5% of the gross income.

There is no CGT liability while units are in the trust, but there may well be at encashment.


...I am getting there!