BRITISH RAIL TAIL LAMP FLASHING RED LED REPLACE DAMAGED CIRCUIT 2N3904 2N3906 EOT

I bought off eBay and unfortunately it's battery had leaked ruining the circuit so I constructed a replacement using 2n3904 and 2n3906 transistors and 9 bright red LEDs. I wanted it to look similar to the original and flash a short pulse every 0.5 seconds which it does. 😄👍