Best bet is Ryan, Lockett, Mitchell, Waite Sanderson, Whetmore, Norweb, and any of the large gold collections in the past 30 years. Sorry, I don't follow gun money.
I should have said that if you don't have any joy in Montagu, then move onto Murdoch. Part IV had both the Montagu shillings plus a crown and halfcrown. Unfortunately all were bought by dealers (Spink and Whelan). Lots 62 - 65 refer.
If uncertain, always start with Montagu assuming it is in the time period. Part IV lots 282 and 283 were large and small shillings struck in gold, but I have no idea where they went or even if they are still outside a museum. They weren't illustrated.
I hae trickled out the surplus over the years. I even have a handful left to go, but if I was to sell the collection I would then have to start again. I don't believe I could reassemble it in either a reasonable timeframe or in suitable quality. The last 5 or 6 years have been very difficult to find things to add at reasonable prices.
Anglo-Saxon has been under a bit of pressure due to the quantities being found. If you are digging up say two dozen Offa pennies every year, this has to impact on the prices - which is one where there has been a softening of prices.
Looks like Davies 1096 (5+D) to me. I of GRATIA to bead, 8 beads A to A on the obverse and faint cross touches left of bead, 10 beads covering date. This pair also exists for 1880, though Davies prices suggest it is scarcer than the obverse 6 for this date. This has I of GRATIA to space and 11 between A's. ESC is useless around 1879 for shillings certainly,and now it appears for 6ds too.
The other problem with 'returns' is that you cannot really 'mark to market' for a piece that is so rare that there is no market. So the value that gets put on it is what you think someone might pay rather than a solid history of similar coins fetching given prices over a period of time. Correct. It is the same conundrum from the stratospheric pieces all the way down to a grotty washer of which there is only one known - there is no market to provide a guide price. I often have people visit the table, but shy away from a pattern because they aren't comfortable paying £xxx for a piece that isn't listed in the standard price guides. It is probably a good job, as they might become unaffordable across the board once everyone has a reference point, given their absolute rarity in many cases.
A significant number are out of reach of any collector. There are some commoner pieces on the list such as the Henry VIII testoon or 1841 halfcrown, many of which are held by ordinary collectors. It is mainly a list of seriously rare coins. It's safe to say that if the 'investment' chaps stuck to that list, they would take a very long time to build up a portfolio. The plantagenet hammered gold is fairly abundant as is some of the milled, but the tudor gold section contains some serious rarities as does the Saxon.
A more detailed look at the SG list suggests that it is a bit disingenuous. Apparently the only St. Martin of Lincoln silver penny in private hands has returned 12.1% over the period, whilst the equally common Henry III gold penny has done over 15%. Yeh, right. The Scarboroughs are not freely circulating either. There are a lot of pieces on that list for which the return is a lick your finger and see which way the wind is blowing number.
https://www.stanleygibbons.com/medias/sys_master/8861642424350/coinindex2012.pdf Very interesting. Only one coin on there that would interest me. It struck me too that many of the pieces there are out and out rarities which have always created a free for all when they come around. Given these buyers are not driven by collecting motives, one can only assume that the strength outside the 'investment' pieces is simply due to increased demand from 'normal' collectors. Bit of a blurred distinction here as many 'normal' collectors don't like parting with their coins for less than they paid. Having said that, a person I am familiar with wanted to buy for investment reasons, but wasn't patient enough and so lost money on the sale. C'est la vie.