This has appeared in Lake Lothing, Lowestoft in the last few weeks
BOSS ex-TROMPER WIEK (WWDI/3) - DDR patrol boat type KB-23, built by VEB Yachtwerft Berlin
http://www.mk-köpenick.de/YWB/Archiv/02/1587%20ff/1587-05%20Tormper%20Wiek/1587-05_Tromper-Wiek_BST%20Dintelsas_2016-04_Bild04a1a.jpg
http://www.mk-köpenick.de/YWB/Archiv/02/1587%20ff/1587-05%20Tormper%20Wiek/1587-05_Tromper-Wiek_BST%20Dintelsas_2016-04_Bild03a1a.jpg
and some from 8/2015 at Antwerp about halfway down this page:
https://www.bloggen.be/cricri2/archief.php?startdatum=1439683201&stopdatum=1439769601

Not sure whether she is now a yacht or something else, with that A-frame.