What's the right way to repair damp proof membrane?

[ozymandias]

We have just had a big hole dug in our kitchen to find and seal an old lead pipe which (for no apparent reason) suddenly started discharging 6000l/day into the space between our wall and next door!
What we are left with is a 30cmx90cm hole in the floor by a wall, which goes right through the plastic damp proof membrane (ragged edges visible half way down the hole). I am concerned that the 'easy' repair is just to fill the hole with concrete. There's your floor, mate - we'll be long gone by the time the damp starts coming up...

Is there an accepted way to repair the membrane (some special gunk, resin or something?)

Regards,

Oz.

 

[noseall]

Just lap the repair piece of DPM up the sides of the existing concrete a couple of inches but keep it below the surface so that it does not spoil the finish.