Yield versus Price

If u buy a Trust at 100p yielding 10% a dividend of 10p.

If the the trust doubles in price doubles and the dividend is still 10p, the yield is now 5%.

In the future when one of your Trusts doubles in price, u can either.

Sell half and re-invest in another higher yielder, an option if the dividend has increased over the holding period, or sell all the position and try to do it all over again, all depending on the yields in the market at the time