UK Model Crown And Ceylon 1/4 Cent

Nice pieces. I have a bunch of 1/2 & penny models, but no crowns. These are increasingly being referred to as bi-met's. Some nice images are here:
http://www.wbcc-online.com/grtbrt/grtbrt5.html

The "model crowns" and their companion pieces, the "model pennies" of the same time period, were private patterns, made by people who were lobbying for coinage reform and had ideas about how to about it. The theory was that the silver crown was too large and cumbersome for everyday use, so to make it smaller while still containing full metal value, they should be made bimetallic, with a silver ring surrounding a tiny gold core. Likewise the penny could be shrunk by making it bronze with a tiny silver core.

Of course, these models didn't actually contain any precious metal; the "gold" was just brass or gilt copper while the "silver" was white metal. The mintages are unreported but these model coins were popular, to the extent that the Mint actually had to issue a press release informing people that these models were not actual coins. Some types may also have been issued as play money.

In the end, the ideas were rejected and bimetallic coins would have to wait another 130 years before being re-discovered and issued by Italy in 1982. The large copper penny was reformed in 1860 by shrinking it slightly and making it bronze, while the crown remained a large and cumbersome chunk of silver.

You can find these model coins listed in the Krause "Unusual World Coins" book and on NumisMaster. I believe yours is KMX# 24, the commonest type.