Hi Lisa23,
TNA has a page explaining what they charge beyond the £8.40 "Page Check" fee. Scroll down to the section subtitled "Copies of Records – less than 100 different pages of records". Here's the link:
https://www.nationalarchives.gov.uk/help-with-your-research/record-copying/fees/If I've read it correctly, their copying service is less expensive than I imagined...certainly, as Mckha489 says, cheaper than a plane ticket. But there are a few things it might be advisable to keep in mind:
Firstly, the page check includes them "reviewing the document to assess if the information can be located" and "checking its suitability for copying". See:
https://www.nationalarchives.gov.uk/help-with-your-research/record-copying/ So if they were unable to find the information you're seeking, or it's unsuitable for copying (which I guess means too fragile or possibly something else), it appears that you would receive absolutely nothing - apart from a "we're unable to..." message - in exchange for the non-refundable fee.
Also, as you mentioned, the record you're seeking consists of five documents and (if I've not misunderstood) you're unsure if the £8.40 fee would cover all five. Whether it would, or whether you'd need to pay £8.40 for each of them (i.e. a total of £42) is not very clear, in my opinion; but it does say "reviewing the
document" rather than "reviewing the record" which could mean £8.40 each. The only way to be sure is to contact TNA directly and ask for clarification. They offer a live chat service but if the time difference between Australia and the UK presents a barrier to using that, they also have an enquiry form. Both can be found here:
https://www.nationalarchives.gov.uk/contact-us/make-a-records-and-research-enquiry/NB: Although the page is headed "Make a records and research enquiry", the form and live chat are also for enquiries about record copying, as stated on these pages:
https://www.nationalarchives.gov.uk/information-management/keeping-touch/contacts/https://www.nationalarchives.gov.uk/contact-us/Secondly, if you decide to place an order, it may be best to order a digital copy because the cost of postage and packing for a paper copy would be in addition to the copying charge (and probably not cheap). See here:
https://www.nationalarchives.gov.uk/legal/record-copying/Thirdly, on top of the TNA fee, your bank might charge you for a purchase made in a foreign currency (£sterling), rather than in A$.
Fourthly, the record you're hoping to get copied seems to be among Greenwich Hospital School Admission papers. I've never looked at those but other school admission papers I've seen provide only a few details for each child - no more, or hardly anything more, than is contained in the record description on the TNA website. So the five documents in the record (which I guess relate to the five named siblings) could each be no more than one sheet in length; and, apart from details of the relevant child, be filled either with lots of white space or with details of other, possibly unrelated, children who appear on the same page.
To sum up, despite TNA's copying charges apparently being less prohibitive than I anticipated, you might wish to consider whether you're comfortable with the total cost for potentially, at best, a very small amount of data.
If you do decide to place an order, TNA advises that page checks normally take up to ten working days to complete and copying normally takes up to 14 days (but may take longer) - see here again:
https://www.nationalarchives.gov.uk/legal/record-copying/Good luck with your research,
theirchild