Hi Jamie,
This may be a bit late in the day now but, I've found that supermarket meat works best rather than that you buy loose from the butcher. I have no idea as to why this is the case, but it does make a difference I find.
Also, as Gary mentions, thick skewers are so forgiving when making seekh kebabs. I picked up mine for about 1.50 each I think.
One more tip, I always shape my kebabs with cold, wet hands. 1, it's stops the meat sticking, 2, it makes shaping them really easy and quick and kind of seals the outside of the kebab.
Hope that helps mukka!
Ray
