doug2222usa wrote:You really should check for rare dates before you sell them for bullion.
That would be sage advice for anyone picking up this thread after a while, thinking "my coins are just like Aerogi's".
"One size does not fit all", but I did check them for the OP, before arriving at my answer.
I see 1879M, 1890, 1899, 1901, 1902, 1911 and 1927 for the Willhemena.
The 1879 would have been interesting as a UK issued coin, but it has a small M under the bust, meaning it was produced by the Melbourne mint.
Here's a typical Mebourne Mint coin (Not 1879), but it shows you where to look .....
and from Aerogi's copy ....

1879M is a very common variant. People see the 1879 and think they've hit paydirt, but you often "flip them over, to disappoint them"

.
It also brings me to condition. You can see from the first image, that a high grade has a lot of detail in the hair band, and hair strands generally.
Aerogi's copy has a lot of wear, indicating it was probably "a circulating coin".
In terms of practical grading, most bullion coins only attract a slight premium for better condition grades, except for the two highest grades (EF / UNC).
I know in America, grading companies like to "steal a grade" by their "objectivity", but that $30 fee only adds about $25 to value (and then, only for the first purchaser).
In the UK, you can often see bullion coins, right through to VF, in the standard bullion drawer, with no premium at all. (Sure, they might try to convince bunnies to pay a small premium, but that "love" evaporates, when they buy them back!!).
What has changed significantly in the intervening six months (since I first wrote), it the price of gold, which has pushed Sovereigns up about 10%. (GregN - you were right

).
... Hypothetical, of course, unless you actually traded some in the period.
Gold has always been a bit of a rollercoaster ride. Big highs, big drops.
I think the current market turbulence, with the gold:silver multiple standing at 101.9, leaves a huge upside in silver (If "dabbling in metals" is "your thing").
Any medical cure usually requires tonnes of silver, and we don't hold big stockpiles.....
Whereas gold? We are awash with it (Even after "Covid-19 commemorative coin" demand

).