I had a Astra van. 1999-2004 model.
Had a 350ltr flat tank in the back, one reel, pump battery etc and a little space. Was very weak when fully loaded with water, but was the best my budget could afford.
Looking again, I would probably search for a cheap, Berlingo, Partner etc.
I wanted the Astra as it looked better, but wasnt the most practical.
And every Astra van including my old one, I have seen, smokes!!