Possible Clues:

• That's enough to put one off being a tenant
• Something that puts off
• It discourages someone from doing something
• Tending to put off
• Nuclear weapon — maybe slight damage round land across the Channel
• Something intended to discourage
• Preventative measure requiring investment ultimately: maybe does payment to cover it
• Something discouraging action
• Something designed to be off-putting
• It acts to discourage