In message , at 16:39:03 on Fri, 19 Feb
2016, Mizter T remarked:

On 19/02/2016 16:25, Roland Perry wrote:
[...]
To the OP: You'll get pretty much the same fares and availability from
any site, unless the train company has "Web only" fares, which I don't
believe are available London-Bristol.

The two ways to save money on the "appear on the day, possibly during
the rush hour" fares is to look at off-peak fares which are sold for any
qualifying train, or so-called "Advance Purchase"[1] which are only
valid on the one train you specify when booking.

[1] While you can buy all the tickets before you travel, "AP" is the
industry jargon for the ones where you specify in advance exactly which
train you'll be travelling on. They can only be purchased on the day
before travel, and earlier.

Sorry but no it's no - AP can just as easily be considered an
abbreviation for 'Route: Any Permitted'.

That's completely wrong, because it's never abbreviated like that on the
tickets.

They are called "Advance" tickets, pure and simple -

Which can easily be confused with walk-up tickets purchased in advance
of travel.

no need to introduce complexity by using a non-standard abbreviation
that you appear to favour but is by no means industry standard.

http://www.arrivatrainswales.co.uk/L...in/HowtoBuyAP/
--
Roland Perry