Can you provide a link to this information on the
FGW▸ website? I'm struggling to find this list you've given.
There should be no evening peak restrictions inbound from Reading. The operator is not allowed to set any. It would be against their franchise agreement.
The outward portion of a Reading - Paddington Off Peak Return (SVR) is valid on any train after 0930.
Restriction code 5BThe outward portion of a Reading - Paddington Off Peak Day Return (
CDR▸ ) is valid on any train timed to arrive London Terminals after 1000.
Restriction code C7The return portion of a Paddington - Reading Off Peak Return (SVR) is valid on any train after 0930.
Restriction code 5KThe return portion of a Paddington - Reading Off Peak Day Return (CDR) is effectively unrestricted, although you obviously can't return before the validity of the outward portion, which is valid on the 0921 and later from Paddington. There are no afternoon/evening restrictions inbound from Reading.
Restriction code J9Any greyed out services on booking engines are an error. A long standing fault that FGW either can't, or can't be bothered to fix.