Allan studied at both Swansea and Coventry Art Colleges. He graduated from the latter with a degree in Fine Art.
For a number of years he was involved with illustration, working for most of the major British publishers. However, he gradually drifted back to his first love: landscape painting, specialising in pictures of the Gower Peninsular and the mid-Wales area.
His work has been influenced mainly by the Pre-Raphaelites and Impressionists such as Monet and Degas.