Literary Agents – how to find a good one and why I chose an agent based in London

I was prompted by a feature by Catherine Heaney in today's The Gloss (The Irish Times magazine) to write about agents. The piece is mainly about Irish agents and I've often been asked why I don't have an Irish agent. I'm represented by Lucas Alexander Whitley, LAW, and in particular Philippa Milnes-Smith and Peta Nightingale. [...]