Seat Leon water leak

[sheffcortinacentre]

Got an 02 seat Leon hatchback & it's started fulling the passenger rear & drivers front footwells with water over the last fortnight ( but not the opposite ones) squelching when you get in!

I've sat in it during heavy rain & can't find where it's coming in. There's no sunroof ( so presume it's not filling the sills & over flowing),headliner is dry,boot is dry,I've put talc on all the door rubbers ( no trails) , checked the bulkhead,arch liners are intact, solid underneath ( no cracks in underseal). Parked on level ground, regularly garaged until this year.

The amount of water ingress it should be pretty obvious were it's coming from but I'm stumped, don't wanna drill floor but it's heading that way .

So has anyone had this problem with one? 

[comfortablynumb]

Tried the hosepipe trick? 

[Mally]

Drilling the floor never failed for me. There may even be a bung that could accidentally fall out.