Ok recently I got this cheap white led lamp with magnify glass, all good but when I open it and have a look, the leds are driven directly from 240v main with a resistor, and a bridge rectifier.

It doesn't look safe, so I'm thinking maybe power it from a 12vdc with a booster converter.

So should I leave it as it is, or make a boost converter and power it with 12v, is it practical? If not, what are the other options?

My goal is make it safer to use. (And I want the LEDs last for a reasonal amount of time).

The LEDs draw about 8mA, 40 in series, and I really don't want to resolder them in parallel

 

You use a lot of resistors, and figure what you need for 12V (or 24VDC, or 48V DC). This circuit is not safe, and is in direct violation of AAC Terms of Service

LEDs, 555s, Flashers, and Light Chasers

Soldering LEDs in parallel does not work well, this is explained the above link.