Historically when Gold and Silver Bullion has been purchased in Scotland, the Bullion Dealer has offered to store the physical bullion for the buyer in a vault overseas. No vaults were available in Ireland to securely store large stocks of bullion, hence overseas vaults. These vaults are typically located in countries such as Switzerland, Singapore, US, Germany & Australia. Bullion dealers generally charge a storage fee of 1% of the value of the bullion per annum. This storage fee will be slightly less if you have a large amount of bullion. The downside with this storage option is accessibility and ease of sale.
Another popular method of buying bullion is The Perth Mint Certificate Programme based in Australia. The bullion is stored in a government owned mint and you are issued with a certificate that details owners name and amount of gold that is stored on your behalf. Downside once again, is accessabilty. In addition, market skeptics suggest that the Australian government could confiscate the bullion if severe financial hardship was endured by the Western Australian Government.