So 0.1% per month, assuming you plopped £100 worth in, and it remained at £100 all year would mean you have £98.91 by the end of the year left, so that’s an annual fee of 1.2%(ish), I tried to do an APR but failed in my maths.
When you consider a management fee in the Invesco Physical Gold ETC is about 0.24% per annum, this is quit an expensive way to buy gold.
Not entirely sure what solution this product is trying to solve.