First point is that Havering will not re-offer the discount if you submit representations. That means if you do submit them, it means it becomes a total no-brainer to take them to London Tribunals, because the penalty remains the same, and there are no additional costs. But Havering do have costs, being the cost of preparing the evidence pack and also paying the adjudication fee.
Looking at the two PCNs, I think the one for South Street/Havana Close would be harder to win at LT, because you are faced with the restriction sign, yet drove straight past it. For South Street/Eastern Road, you need to tell us your approach to the station underbridge. Was it a left or right turn, or just straight over the cross roads. There has been a win here, see Case Number 2240307021 in the LT Statutory Register for the Environment and Traffic Adjudicators.
You might also care to look at Case Number 2250496292 which seems to match your circumstances entirely.
So really it's all down to your attitude to risk; cough-up now for £80 or take the double-or-quits gamble at London Tribunals.
