Yes. If you are a UK tax payer, then you can have a Penfold pension. This means that you are paying income tax in the UK on your earnings. So, you don't have to be a UK citizen, and you can be living abroad you just have to make sure your income is UK based! Please just make sure you enter your UK-based address when you fill out your personal details.
If you retire abroad, you can still contribute and withdraw your Penfold pension, at your UK marginal tax rate.