I copy and paste the https etc in the box at the very top of the screen.

I've not found a replacement 3rd party photo hosting site yet - hopefully Imgur and the UK regulator will get their sh*t sorted!

Ian, thanks for picking up the ball and running with it.

I gave the link and went through the annoying process of posting photos because you gave a lot of part numbers, but a lot of us have learned that some ebay sellers will assign an old sock a Yamaha air filter part number if they found it inside an airbox on a junker they dug out of a field.  

Far more common and even more tricky is part and bike miss identification by sellers.  

The ebay item you shared is definitely NOT the larger M or MX airbox.  Looks pretty rusty though.  

I'm not enough of an expert to positively say that one is correct for your bike, but it looks very much like it is.  I'm 90% sure but there could be some little detail for your year/model that I'm not aware of...  like I remember some of the earlier models may have had louvers on the side?  If you're looking for "concours original", those details might be important to you. 

 

The early DT1 airboxes has side louvres , but they were gone on the 71 model .
My parts book shows both 70 & 71 RT1 boxes not having side louvres .
The airbox on Ebay looks the same as the 71 DT1 , which takes the same air filter as an RT1 ,
but has a different prefix on the part number . Obviously there must be a difference between 250 and 360 boxes ,
perhaps size of air intakes ?
The Ebay box should work for you , but as Mark has pointed out , it's in a pretty sad state .

Thanks guys.  I may still go ahead as I have nothing at the minute and I am sure I can make it work.  

I will think over night.  

cheers to all