"Merryterry2000" wrote ...
The soil on my tiny veg patch has become very acid through application
of garden compost over many years. The top surface has a green sheen
to it when dry which I assume to show an acid condition?

What do I do to quickly bring the condition to, say neutral?

I expect I will be told to add lime but how much to start with?

You will need to test the pH, kits are available and there are also
electronic testers at about £14. Of course there are professional ones at
silly prices too.
When you have tested it and got a pH reading then you will have some idea
how much lime to spread on it to bring it back to neutral, pH7 .
We use a 25Kg bag of lime every year on our brassica bed.
--
Regards
Bob H
17mls W. of London.UK