Ok so first off i was coming home the other day and my belt came off, got my car home and sussed out why, power steering pump was rooted and shaft was moving back and forth, anyway new pump and pulley put a new a belt on but in the meantime, (2 weeks ish) my battery wasw pretty much dead, nothing was happening when i turned ignition. was on a hill and its a manual so i wasnt worried, anyway roll started it and the sudden jerk of the roll start must of been to much for a new belt it came off again, so another belt later i put it on put my battery on the charger and thought il try jump start it off my mums i20 lol dunno if it wasnt enough juice to start my car or what but same thing again nothing when i went to turn key over, just the dash lights turn off like normal but no starter turning over and the handbrake light remains on when i turn key as well, i checked fuses and relay incase it was something else as well or could it just be a completely dead battery? im gonna leave it charging over night see how that goes, just hope its not something else as well. I also need my car urgently on tuesday. any tips? ideas? suggestions? cheers guys

I also just recently fixed a coolant leak, heater core was f**k, didnt replace just joined the in and out where the pipes go into the firewall so no heater, did this while car was off the road as well while waiting for the new pump, was a bit messy and tight to get my hands under the intake manifold to do this, could of got things wet around there if that could of done something?

oh and this manual is a conversion, reverse lights dont work either and will only start in neutral

Have you checked you haven't knocked the neutral switch on the gearbox when you were replacing the heater hoses or any other wires in the area?

Does the Smartlock light turn off when you try and start the car?

Double check the alignment of all the pulleys as well, the belt should not throw out even with a rolling start, especially a new one which is quite tight.