From 1996 to 2000 I bought copper and bronze UK pennies and sold them in 2013 at LCA, along with Cromwell Crown, half crown and shilling, 1911 long set, 1937 long set, to raise some cash.. There was a good profit made but I have noticed that category of prices has gone steady or even down, for the pennies, in recent years. So I think I sold at the right time, the proofs have increased in value though.
I was only divesting 20% of my savings as you seem to be doing the rest is in income producing stocks and trusts but of course there will be another downturn, no one knows when of course but sure to happen with valuations being what they are.
I have bought some 2017 sovereigns, Piedfort, BU plain edge, only due to mintage numbers being so low. I think they are speculation for investors but at least they are gold.