SO - i see it the other way around: Brown might have wanted a coalition deal with the LD's, but the LD's wouldn't touch him with a barge pole because of his political toxicity, despite Labour being, probably, more comfortable bedfellows than the Conservatives.
i'd see the SNP being similar - can you imagine the damage to Labour in the North if they imposed swinging cuts on services in England but exempted Scotland from such pleasantries?