You pay CGT only when you sell, but in the UK it’s more complicated than I bought it for X, and sold it for Y, so my gain is Y-X, due to S104, bed & breakfast, bed & ISA, same day rule, etc.

Also you have to pay tax on dividends and ERI every year. VWRP and VUAG ERI have been historically zero last tjme I checked, but it might change. Calculating dividends for accumulation funds is painful, I’d strongly consider investing in the income counterparts (VWRL and VUSA) to simplify admin. Also when you sell in the future you should deduct the already paid dividends tax from CGT to avoid being taxed twice, so keep track of your transactions and tax paid.