Paddington to Newbury Off Peak Return

Hello! I am planning a trip which will be Paddington to Newbury, leaving on a weekday afternoon and returning at the weekend.

While I might be able to get to Paddington before the evening peak, I can't guarantee it. I'm looking at the Off Peak Return which has restriction code FP. I am confused about its restrictions. Some booking engines and websites suggest that this would be perfectly valid at any point in the afternoon and evening; others say it is not valid and I'd need to purchase an Anytime ticket.

On National Rail, typing code FP gives me restrictions (which are for the morning peak only) yet the booking engine won't let me select an off-peak return.

BR Fares suggests FP also has some 'unpublished restrictions', which bar me from using the outward portion of this ticket during the 'evening peak'.

Trainsplit suggests an Off Peak Return is perfectly valid at any time in the afternoon/ evening (say 1630 as an example).

Needless to say, I am confused. Is there conflicting advice? Have I read it wrong? Would anyone be able to offer some advice here?

Typically, longer distance trains from Paddington are barred during the evening peak, and this is shown on BRFares (and implemented by the booking engines).

The restrictions are becoming more restrictive from the timetable change; if you travel after then, you may find that only fairly slow trains to Reading are stilll available.

Some GWR restrictions are coded inconsistently, so computers (and sometimes ticket machines) force you to pay more than legally necessary. The problems appear to be endemic at the company and have been going on for years (and I'd suggest a prosecution of the company for knowingly overcharging may be long overdue), but the company seemingly is uninterested in fixing them and the regulators that have the powers to force the company to fix the problem or prosecute it are nowhere to be seen.

You need to read the contractual conditions for the fare you are purchasing i.e. what the 2-character code description on the National Rail website says and then abide by those contractual terms. If a website or ticket machine tries to make you buy a more expensive fare than necessary for a journey without warning you, do report it to the company/regulators but don't hold your breath if you expect anything to change.