yes you can, your deed needs to state you intend to invest in PM's, you also need your investment plan to include the proportion of PM's. Then you need to decide where you will be storing your PM's, must be at arms length, write some minutes to theat effect stating the location etc, then get all the trustees to sign the minutes and off you go. I have recently bought some gold also, but if you think youre going to double your money I would be very careful.