Indeed. I checked this out and I think I see the source of the error. I tried to get hold of Kevin Smith to verify, but using google maps I can see the correct position. It will be changed. Thanks for bringing it to our attention!

The position on the chart is incorrect, despite Lat&Long being in agreement with their website

http://www.northreppsaerodrome.co.uk/

The SD chart and the above website locate the airfield at N525352 E011908.

I landed there last week and my SD flight log indicates the airfield to be nearer N525337 E011915, which is three fields south of the charted location.

Happily, I managed to land in the correct location :-)

I have taken a look at Google Earth and confirmed my findings by placing the cursor midway down the alignment of the longest runway.

SD and a cheap Chinese satnav = Jobzagoodun.