fuel leak??

[JRDUNN]

hi i bought my mk2 1.6 uk mazda mx5 for £2000 and with under 50,000 on the clock, FSH, and (very almost) rust free i thought it a bargain. but today i noticed a fuel leak, specifically when cornerning, when i come to a stop theres no spillage and by the time im on my back looking under it for a drip line the fuel has all evaporated so no trail to follow.
this is all happening with around half a tank in the car, this would probably explain the catastrophic fuel consumption ive been acheiving

any ideas? or as i suspect am i gonna have to buy a new fuel tank.....