Hi Richard,
The attribute you need is called 'header' not 'Header'. Remember, the W3C XML specs say that XML tags are case-sensitive!
Tsk, silly me, how could I forget? Still, as a mitigating circumstance, the query was automagically generated by BioMart, I just clicked on the "XML" button and added the "formatter" option by hand. Anyway, thanks for spotting this! Cheers, David.
