I have a galfer rear caliper on my techno and need a new bleed nipple 7mm. Any help out there would be good

Go down to your local brake parts dealer, they stock all sizes of bleed nipples.

On the 99 Techno, the bleed nipple on the rear brake caliper has a ball bearing behind it, which acts as a sort of a valve seal. Without this ball bearing, it will not function properly. Apparently there is more than one type. I got one from BMV recently, but had to alter it a bit to make it fit. It did not come with a ball bearing, so I then had to find a ball bearing that would fit in the seat between the caliper and the bleed nipple. I found mine in the wheel of an old sack truck. Bleeding the bleeding rear brake is a real pain.