My son was trying to fit a new gasket from manifold outlet to first part of exhaust pipe because we heard it 'blowing' - found out that there is no gasket and advised to put Gungum there. However, he has found that the blowing was not from that junction but a hole in the manifold by means of a threaded hollow bolt thingy. I am trying to upload some pics so please 'bear with' if it takes me some time. Thank you.
I tried but even though just one photo photo (of 3) the max Mb allowed is only 2.9 and It may exceed that or it may be in the wrong format. Gawd knows. I'll try to explain The hollow bolt was removed from the main casting of the manifold ablve and to left of the forward exhaust pipe flange fixing bolt. On an expolded view of exhaust manifold in Series 3 parts catalogue download (page or image number 1C 13) it is shown above and to left of exhaust pipe fixing stud on the forward edge of the rectangular exhaust opening. Phew ! ! If anyone can understand that and knows what the hell it is, please let me know - we intend to block it off anyway but are curious to know what it was for. Thank you. brian

Where?

I suspect you have the "detoxed" engine that has an EGR valve connected to the exhaust manifold (the EGR and its fittings are frame 1C14 in the parts book). I think most people have removed these long ago and just blanked off the port on the manifold.

Thanks to you both. Wildefalcon, The lower part of the second of the 2 illustrations was not visible and that is where the hole is.
ExMil109. I think you have hit the thingy on the waist - what you say makes perfect sense so will block it off. Great information. Thank you very much. Does the EGR stand for Everybody Gets Rid ?