Sorry, vacman, but I think we're posting at cross-purposes here.
Worle station doesn't have a manned ticket office (see
http://www.nationalrail.co.uk/stations/wor/details.html): it has just one
TVM▸ - on the up platform: that machine won't sell groupsaves, for example, and
apparently it can't cope with pre-purchased tickets either.
Nailsea & Backwell, on the other hand, does have a manned ticket office - see
http://www.nationalrail.co.uk/stations/nls/details.html and Jacob there is able to help with GroupSave tickets, but not 'Ticket on Departure' queries.
I hope this clarifies the matter?
Chris from Nailsea.