No secure bike parks round these parts (that I know of). the Lowestoft Travelodge is ok, nice and quiet, away from the main population. Can pop by and lend you a cover if you like?
Edited: a good family friend is an Inspector with Suffolks finest, can arrange drive by patrols….
Lowestoft is a dump, full of junkies and alcoholics. High unemployment and few job opportunities. The main industries, fishing and oil have gone. Tourism is on its uppers. I visit there a couple of times a year as my brother lives a couple of miles away from it. It's so depressing. No more violent or crime heavy than any other coastal resort, but a visit could make you suicidal. Best avoided.