Keisergsd

Hi all.. I'm new to the forum, my name is Steve and I'm currently restoring a 130 Pulse Ambulance and a 110 TUM both bought from Withams. I'm looking for some information on a sticker I found on the window of my 110. It's a red sticker which says 'project Shoehorn modified'. can anybody tell me what this modification was? I've searched the web and can only find a couple of mentions but nothing with any detail. Thanks.