On those dates, they will be worth more to keep. There are thousands of QE11 Sov's that have been weighed in for scrap, that makes the ones that survive more valuable in years to come, especially if you make complete sets of half, full & two pound Sov's for a year, or a whole decade. I've got some Victorian sets that I will save for when I retire in about 197 years.
Gold coins that are currency used to be exempt, but the UK gov. imposed full VAT, which hit the market for private investors. A dealer has to add vat on resell figure plus that on his commission when he sells on.
Victorian coins are exempt (apart from vat on commission) and classed as antique. The condition is a factor in the price.
but there are far too many of them around, even of the early 'modern' variety. These were first minted in 1817, and if you get hold of specific Victorian 'young head' coins in very fine condition you'll certainly get more than just the gold content price when you sell. A specific coin from 1853 for example, might fetch over £300.
Like so many fields, sovereign collecting is a world unto itself, and you need to know what you're doing to make any real money.