"enabled into power by the SNP"
This again? Why you continue to spout this garbage is unfathomable. But, just in case you're interested in learning what actually happened in 1979, here it is.
In 1979 the Labour government, which had no majority, was unpopular as a result of a winter of industrial disputes as it tried to keep public-sector pay low.
Scotland voted Yes to devolution but a rule imposed by a rebel Labour MP in conjunction with the Conservatives and backed by 33 other Labour Mps overturned the result, by including non-voters and the deas as No votes (A 'rule' never used in any other UK election before or since.)
Jim Callaghan and Michael Foot wanted to leave the devolution act on the statue books with a view to reviving it afer the election, but English Labour MPs vowed to block the plan, leading to the vote of no confidence.
At this point, Callaghan accepted that the writing was on the wall and resigned himself to an early election, even if he had won the vote of no confidence. The idea that losing the vote hastened the election significantly, thereby preventing Labour from recovering support in its remaing few months is, by Callaghan's own admission, completely false. Labour weere now so unpopular that the country voted the tories in by over two million votes, and they continued in power for the next 18 year until being thrown out by Blair's landslide victory in 1997.
Callaghan blamed the election defeat NOT on the SNP but on Labour's own weaknesses over the Winter of Discontent and the self-sabotaged devolution bill. He graciously attributed the tories' success to the former issue, and also their promises of tax cuts.
As well as 11 SNP Mps, 13 Liberals also voted in favour of no confidence, along with 8 other MPs from mixed parties.