Sorry to tell you, but when I look at those photos I see one clear yellow line and one that is partly obscured by leaves. If you thought it was a single yellow, but found no sign giving the times why did you continue to park there ? It would only have taken a moment to partly clear some leaves and see the second line, but you didn't. Lines obscured by leaves has been seen quite a few times on this and the Pepipoo forums and outcomes are usually fairly uncertain. See what the others say, but so far I see nothing to challenge on the contravention itself. The PCN may contain fatal errors that can make it void, so please post all sides, including the "small print".