looking to remove  the oil filler   can this be removed with a suitable flat piece of bar  or do i have to buy the tool what i will probably never use again to remove it

no one ever removed  a oil filler

I'm sure a bit of flat bar can be used on the indents on the nut.  I actually bought the proper tool which isn't too expensive

https://www.justkampers.com/00-5761-0-oil-filler-neck-nut-tool-vw-beetle-vw-t2-split-vw-t2-bay-1600cc.html?fee=1&fep=961&utm_source=google&utm_medium=cpc&utm_campaign=PLAs&gclid=Cj0KCQjw7sz6BRDYARIsAPHzrNJPMgR0SLRla2DVodJFBEkZ2plk3iC2iaNOyB_iuLyt_ieByJRIzGwaAnB9EALw_wcB

I've got the correct tool but they seldom work, the threads on the tube nuts get really coked up. You usually end up with a very mangled filler in one hand and a crappy chrome replacement in the other.

Tip: Single port inlet manifold seals make very good oil filler gaskets.

think they do a more expensive better tool what expands   instead of   going in the slots 

Yes you are right.  It`s an old school tool but I believe still readily available in differing sizes. Works on the  eccentric cam action priciple and the tool fits down through the centre hole. Spline teeth grab the structure and you twist it free and unscrew the locking piece. Work very well . You need access to get tool into hole and then the tool you will use to turn it. Socket or something similar. Have seen them with hole drilled through to get a rod thro to allow twisting.

Most of the time, if they haven't been removed for 30 years, they snap the top off the filler tube when you try to undo them. So it is sometimes cheaper to buy a new one rather than buying a tool only for the stand to break. The old one's are a pain to clean up as well.

Rob

used a old  push  bike  bottom bracket  spanner came of easily 

used a old  push  bike  bottom bracket  spanner came of easily

Can you post a pic of the tool you used please?

its just  a multiple  style tool for  working on old push bikes it must be 40 years old it has   openings for pedals bottom bracket , headset etc   i just used this with a set of mole grips on the top    first couple of turns were quite stiff then it just came of by hand

https://www.machine7.com/product.php?xProd=11984&xSec=3454
and may be some heat