Pension - returning from Germany

UK citizen resident in Germany takes out German private pension products and pays in for several years before returning to the UK for keeps. Then continues to make contributions from the UK for several years. Uncertain how ultimate pension income will be treated for tax purposes in the UK if products kept to maturity. Also uncertain whether to close out the products and extract transfer value and whether this would be taxable on repatriation to the UK, depending on whether it is transferred into a UK pension scheme or into a bank account.

Can't find a clear answer on this anywhere - so grateful if someone could accept the challenge!