I think you're a bit muddled there. Dividends are usually taxed at source. A US stock market ETF UCITS like IUSA will be subject to 15% witholding tax whether you hold it with HSBC Jersey or IB in Hong Kong. There won't be any extra tax applied in Jersey.
Shares in Link will not be subject to witholding tax wherever you hold them, and FWIW I think HSBC expat only allows for US and UK sharedealing anyway. Likewise stocks or ETFs that are UK based like Shell or a FTSE 100 tracker will be paid without any witholding tax wherever you hold them.
US stocks and ETFs listed in the US like VOO and QQQ, or in HK like 3140, are subject to 30% witholding tax wherever you hold them.