It looks to me as if restriction Q8 applies to the whole journey of a train leaving one of the listed stations before the 'cut-off time', meaning that a ticket with this restriction would therefore not be valid on the 09.03 from Salisbury (cut-off time 08.50) to Bristol, because the train leaves Southampton at 08.23 (cut-off time also 08.50). Is this correct, or does the restriction just apply to stations at which the train calls while you're on it and not those earlier in its journey?