Only bought the car yesterday, maybe I made a mistake in trying to lock it, but the battery is now dead. Any ideas please as can't find anything on google, plus the remote is also dead or doesnt appear to close all doors

two faults?    battery dead as well?      might cause issue below with low volts but more likely just horrid bulbs

nasty LEDs in number plate lights?   cheap LEDs often fail, one fault you can get is flickering as the "bulb" driver is dead

unless you have a rear camer (where additional illumination can help a cheap camera see at night) fitting aftermarket LEDs for the number plate lights is plain stupid and dangerous for everyone as the car behind might not be able to see where he's going

so a bulb could drain the battery overnight

if it was left on yes, but you tend to notice.  batteries often die overnight (especially at this time of year) or something fails to go to sleep and can drain the battery

your title is about flashing lights, this tends to be one of four conditions:

1) your Christmas tree

2) an irate driver wanting you to move over

3) at the back of the car when trying to stop very quickly

4) LEDs going wrong

 

 

So if it's the bulb, why is it still flashing every 30 seconds or so ?

When an LED goes wrong, it doesn't necessarily 100% not work, it can flash in the agonising way of a dying or failed bulb! Cheap Chinese LEDs are notorious for causing issues. To rule it out, put in a standard number plate bulb, yes, they are dim, and boring, but at least when they go faulty, they simply don't work and won't drain a battery...

Ok TYVM for the help, will have to charge the battery tomorrow and of course change from LED bulbs