I run a PE fund and have some understand, so I’m told of how to play a spread. If I was to invest 20k, which isn’t a lot, provided I was happy to lose it, id look at a long game playing with 5 or so EIS investments that gave me some tax money back and a tax free upside, if there is one. I would look at using a syndicate site such as Syndicate Room for this and expect the returns to take at least 5 years to some back. One or two should win you 10x back, the others will crash and burn but you can see save further by claiming tax relief on the losses. That way the actual risk is about 5k of your 20k but the upside is far more, if you are lucky and it works.
Sorry for the spelling, crappy phone keyboard!