It's Matorro, an early (and more unique) version of the Sturmtiger!
This one has a barrel as the one in Kubinka Tank Museum and the extra front armor and no zimmerit!
It is in it's original box and complete (little parts too as far as I can see, the crane too), but I have bought it second hand and left it as it is (so I never tried it running myself).
Price? Throw me an offer.
The dust is free. Will add more on request. 
I live in The Netherlands, shipping app. 18 GBP to UK. More if it needs to be send to Hermann B.
GREAT tank is you want a unique project, this is how my other Sturmtiger ended up:
