St Nicolas' old and new

We have been digging new graves on what was the northern boundary of St Nicolas’ churchyard before it was extended beyond there. In one of these graves the gravedigger had to cut his way past a large stone which he says is the same as the major stones in the church walls (the top picture shows this) and on the other side lower down he found some ancient brick. He also said that the bottom of the deep grave appeared to be at original top soil level. I’m not sure quite what to make of this. Was there a ditch on the edge of the churchyard into which spare building material was flung when some mediaeval repairs were being undertaken? Was there previously a much greater slope away from the churchyard at this point which this spoil and much other later work has levelled off? Meanwhile, the other picture shows the newly installed aumbry in the church just before it was brought into use for the first time a couple of weeks ago.