In reply to mrphilipoldham:
Either 17 or 19 spanner.
If it the hole is overdrilled, it is easy to hammer the bolt fully into the hole, and cover with resin. However, if the bolt isn't over drilled then it won't knock flush and you'll need to use an angle grinder to cut as close to the rock as possible. And then cover the remains with a small mound of resin. For this reason I always think it is best to cut it down first, and then knock into the hole.
For extra neatness, once knocked flush you can use a standard DIY bolt or screw or something placed on the end of the bolt and hammer this, so that the bolt recedes deeper into the hole. Then you can get a very neat finish with the resin in the remaining hole.
Unfortunately the glue ins are harder to disguise. They need cutting as close as possible (without marking the rock - not always easy depending on placement) and covering.
Sprinkle grit/dust over the resin for a good colour match.