So I trawled through the forum here and added this to the top of my reservecaskreceipt.php template page:
rsCASKINFO being the recordset that's on my confirmation page.
I can now include recordset data in my Universal Email email body:
<?php echo($rsCASKINFO->getColumnVal("wbprodTITLE")); ?> ...etc.
Bingo! However I still can't seem to carry over the remaining form data - the customer's contact details:
<?php echo((isset($_POST["resvcaskNAME"]))?$_POST["resvcaskNAME"]:"") ?> ...etc.
Will keep trawling but if anyone has an answer to this I'd really appreciate it. Thank you.