I have l held and seen. decine and loss -my poor choice ! should I sell and reinvest

Under that title Daily Telegraph "Quester" looks at Trusts cosidered as suitable for this aim the Trusts are. PNL. CLDN. CGT RCP. BMG Caledonian has much larger discount at -31%. this would make it attractive as a buy however there will be some reason for this apparent anomaly. Can anyi one comment on this situation please?

I have a holding price has declined recently -is there any obvious reason for this is it something to hold longer term for increase in value?