Thanks for the reply but I didn't find it terribly clear or helpful.
"For buyer protection you must use a delivery service which tracks and confirms delivery. " - yep, I agree and am going to do that.
"You will not be reimbursed for this expense; neither will you be reimbursed for the original shipping costs. These are important considerations in the costs and risk of return. Is the expense worth it, even if you get a refund?" - yes, I'm fully aware of this, but as the cost of returning the item is less than the cost of the (faulty) item, it is in my interests to pursue this.
"Furthermore, the original seller states to refuse delivery if there are any import fees to pay; you may then get charged for the return delivery of the defective component." - what? if they refuse to receive it then it either remains in Chinese customs until it is eventually disposed of, or if in a highly unlikely scenario it somehow it makes its way back to the UK then I'm going to decline to collect it and it will be disposed of by British customs one way or the other.
They chose a co.uk address to seek trade with the UK. So potential returns from the UK goes with the territory of intentionally pursuing UK business, an argument I hope PayPal will see the validity of should it come to that.
"If you send wihout tracking and it takes 8 weeks to arrive you'll never know if it arrives or not, or if it does but seller denies." - at the start of your response you say I "must use" tracking, which I'm going to do, so your own initial point renders this one redundant and somewhat contradictory.
"Evaluate your own risks and costs and then decide what to do." - I can and have evaluated my own risks thanks, the point of this post was to hopefully receive advice and feedback in addition to my own analysis, not simply to state the obvious and say "I have to evaluate".
