Tiny room wanted. Long Term. Mostly Away

I am seeking a non-city-centre room to rent in the Midlands or southern England.
I mostly work abroad but want a place to keep my things and to come back to on rare occasions.
As I will be there approx 30 days per year the room can be small and must be under 100.00 pcm, fully inclusive.

The room should be in a clean state, preferably lockable, in a clean house and the landlord/residents completely reliable and above reproach.

I am prepared to pay 3-6 months in advance for the right spot. Other than that I am a quiet, unobtrusive professional with very low impact on your current situation. Keen to view any time Mon 29th onwards. Many thanks.