Going through it logically, some observations from me, and this is on a PC, so it may differ PC to PC and from an iPad etc. I've also not gone through the whole order process because I've not needed to yet.
1) Now this is incredibly minor, so I apologise for this! Once you've clicked on the event, it takes you through to the first page. On that page, you can see the event, date and time and location. You can also see 'Description' and right under that is a Club logo. Being really pedantic, I'd get rid of that so that you can see some of the 'Description' text straight away on that page. Some people have missed that text (people were asking how long it would take before they could collection but that info was below the logo). I think if the text is visible straight away, people are more likely to scroll down the page. As it is, the vast majority of the information you need is available without scrolling but the odd piece of important info, such as lead time for collection, isn't.
2) When you click on 'Tickets' it should, IMO, take you straight to the Stadium Plan. As it stands, you select the number and type of tickets you require and the system automatically assigns you seats. We saw during the PSF's, and for the Morecambe game by the looks of where tickets have been sold, that people either aren't aware, or don't know how, to move their seats. Going straight to the Stadium Plan and allowing people to select their seats without de-selecting/selecting. Just switching those two steps would be much more user friendly.
3) For away games, it seemed as though there were two types of sales - ST and general sale. During the general sale stage, you were greeted with 'unavailable' when trying to select a ticket. It wasn't until you scrolled down that you saw there were other sales (again, just Adult, Concession, Junior), which you could select. The general sale types could do with being at the top of the list so they're not missed.
Other than that, it seems to work quite well (without actually going through the whole process).