Yes they do refute it: while the talks were still secret Chinese officials were mentioning that "China will formally announce their decision to recover HK", i.e

Yes they do refute it: while the talks were still secret Chinese officials were mentioning that "China will formally announce their decision to recover HK", i.e. the UK had 2 years to make the handover public, or China would step up, no officious arrangements accepted. Additionally, TFA notes that China had HK and Macau removed from the "non sovereign territories" UN list years earlier, so that both couldn't aspire to independence. Considering that HK was lost following the Opium Wars and the first of the "unequal treaties", something that was considered a deeply humiliating episode in China's history, it's not surprising that their government wanted to "right that wrong". Thatcher was simply delusional about her initial plans ("I really don't understand why they don't want to renew with us this thing they call Unequal Treaty?")