Celebration – Rosie Thomas.

Fontana Paperbacks, 1982.

Annabel Farrer was an independent girl – and proud of it. Good at her job, a success in a man’s world, she enjoyed her life, but avoided any love affairs – especially when the mad had a reputation like the Baron. Then suddenly there were two mwn in her life – both difficult, both demanding, both deadly enemies… suddenly love had taken over her life.
Only the lucky winner would join the final Celebration.