I didn’t! But I did catch them at the Peel in like 2005 at the Gravity Xmas Party, with Hell Is For Heroes! Top, top fun.
Never saw ET:11, but I did see Instruction a couple of times, plus Capdown. Both supported by Twofold, who were the best Gravity band imo.
Here’s a shit video of them from ages ago. Can’t find any proper audio, but if you see Dance To The Rhythm anywhere, give it a spin.