Many thanks guys, it's nice to get something done again especially when people like it!
Roger, the inlay is shown below. There is some foreshortening due to the angle at which the pic was taken. However, the major/minor axes are in exactly the same proportion (3:2) as the table top itself.
It wasn't too bad cutting the recess. I used a powered router for the bulk of it, then as I got closer to the edges (I had previously incised with a scalpel), I used a Veritas router plane which let me get right up to the line without any real drama.
The hardest bit of the inlaying was satisfying myself that it was in the right position. The grain of the wood fools the eye and I kept wanting to set it on a skew. This looked fine from some directions but wrong from others. It took close to an hour before I had convinced myself that I had it as good as it would ever look (which was, unsurprisingly perhaps, the geometrically accurate position).