Had the iPad three years and the battery life isn't fantastic now.

The various non apple chargers take a while to charge and the battery drains quickly.

However I stupidly let it go completely dead and I am getting the battery sign with the red bars and nothing else.

Is my only hope of redemption to try and charge it in an apple shop and buy an expensive charger as there won't be enough power coming from a non apple one I assume

IIRC iPads of that era charged at about 2.1 A. if yo can find charger or even a power pack that can charge at that amperage you may be able to save the battery.

Thanks I will go into the apple shop tomorrow

I went back to Apple leads after the sam3 experience as you or at least Apple MFI certified ones