Just a quick comment on why Labour needs to mount a proper challenge in Scotland. I know some people south of the border, think this a bad idea partly because they have an unrealistically gloomy view of our prospects and partly because some of them think of the SNP as being some kind of ersatz Labour.
On the first, the SNP are in a weak position. They have failed Scots particularly badly on education and the NHS. Their reputation otherwise is based on Sturgeon's admittedly impressive PR skills and effectiveness in blaming England/the UK for everything. The Salmond/Sturgeon hostility is likely to spill out during this Parliament and allow Scottish Labour to be heard again.
Secondly, the SNP are not Labour's friends. Their grip on power depends on a weak Labour. Their ultimate objective is destroying the UK.
Just take the comments Sturgeon made about quarantining people from the UK. Her motivation is similar to that of Priti Patel, blaming outsiders for disease is an age old technique for nationalists. It is designed to provoke the English as well as stoking poor relations between the North and South. Of course, it is not a policy that could be enforced as Holyrood has no power to install border controls, and families living on both sides of the border would deeply resent it.