Blandings
You appear to forget that both in 1979 and 2010, the Conservative’s inherited from Labour a national emergency, and their early policies trying to get the UK back on its feet, were a direct result of Labour’s ideological mistake, that the UK state can be larger than the private sector supporting it.
You mention oil, that came ashore from the North Sea in 1976, around the time Labour had to call in the International Monetary Fund (IMF) to financially bail us out with their now better known strict repayment plans, forcing a government to cut spending.
So as the UK went into 1979, there was the ‘Winter of Discontent’ when the militant UK trade unions took on the Labour government, with pictorial evidence in the link below.
“Before Thatcher Came To Power (1979), The UK Was Literally Covered In Gigantic Piles Of Garbage”
Yet people talk as if the 1970’s pre Thatcher was our FINEST decade;
When UK manufacturing fell from around 30% of our economy to around 20% (when little else to compete with it), as mass strikes were killing UK industry, inflation/interests rates/pay rises around 15% plus, the basic rate of income tax over 32%, the highest income tax rate up to the 80%s, the tax on unearned income e.g. investments, around 96% - and if a company dared made a profit, they paid 50% Corporate Tax.
And so yes as Thatcher attempted policies to solve all the above problems Labour were unable to pre 1979 - our international competitors like Germany and Japan never had - things did get worse for a few years, but the economy/employment grew from the early 1980’s and oil receipts (probably still paying of the IMF) were a small part of the economy back then.
As for VAT rises, as opposed to other taxes killing the growth and incentives to work in the economy, there was a part of the huge Budget Deficit Labour left, called the ‘Structural Deficit’;
UK [[http://www.bbc.co.uk/news/business-25944653 Structural Deficit’
”The structural deficit is basically the current budget deficit, adjusted to strip out the cyclical nature of the economy. You would expect, for example, the budget deficit to narrow when the economy grows after a sluggish period. The structural deficit attempts to exclude the effect of this recovery.”
”In other words, the structural deficit is the bit of the deficit that remains even when the economy is operating at full tilt. Or put another way, it's the underlying deficit that is not directly affected by economic performance.”