Please be aware that gold coins are not eligible for investment as part of your UK SIPP. The only form of precious metals that you can invest into are gold bars or wafers that have a minimum purity of 99.5%
Many UK firms are offering gold investment accounts, however, several don’t make any distinctions between a standard investment and a pension investment. This means that there are no built-in restrictions on the types of products you can buy through them, which opens up the possibility that you could buy gold products that aren’t eligible for pension investment.
Whilst the gold coins are pure enough to not be subjected to VAT or Capital Gains Tax, they are absolutely not eligible for a UK pension plan.