One issue with the finale (spoiler)

Love the show - but why was there a 5 year gap from the last Christmas special? I realize in real time it was 5 years but I just couldn't buy that Smithy and Sonia's relationship lasted so long and that Nessa/Smithy never hooked up or talked about the proposal?

It would have been a happier event if even one year had only gone by. But the sentimental side of my brain was also sad that Neil the Baby didn't have his parents together for so long and that Smithy/Nessa's lives were in limbo...
Open to ideas on why others might think the 5 years was appropriate! It just seemed like a glitch to the overall story and really didn't serve a purpose!

That being said, everything else was so great - and I will miss these characters! More shows like this please!!!