The long answer which appears quite generous:
From National rail website, note overnight stop is not defined as a break of journey.
http://www.nationalrail.co.uk/times_fares/ticket_types/
When can I use an Anytime ticket?
Anytime Day (Single and Return) tickets must be used on the date shown on your ticket and up to 04:29 the following day.
Anytime Single must be used within 2 days of the date shown on the ticket and up until 04:29 after the last day of validity.
For Anytime Return tickets, the outward journey must be made within 5 days and up until 04:29 after the last day of validity; the return portion must be used within one calendar month and up until 04:29 after the last day of validity.
Off peak
Off-Peak and Super Off-Peak tickets may require you to travel at specific times of day, days of the week or on a specific route.*
Off-Peak and Super Off-Peak tickets are valid for travel on the date shown on your ticket and until 04:29 on the following day.
Off-Peak Singles and the outward portion of Off-Peak Returns are valid for travel on the date shown on the ticket and until 04:29 the following morning. If the journey cannot be completed in this time, the ticket may be used to continue the journey on the following day. Unless otherwise indicated in the relevant restriction code, time restrictions apply as*from the initial origin station on both days. The appropriate restrictions for the actual day on which travel is being undertaken apply (for example, it may be that if day 1 is on Sunday, no restrictions apply, but on day 2, the Monday-Friday restrictions apply). All travel must be completed by 04:29 in the morning*after this second day. Please note that break of journey is not permitted on some journeys, as detailed in the ticket restrictions.
Return portions of Off-Peak Return tickets are valid for travel until 04:29 on the day following the last day of validity (i.e. one calendar month from outward journey). All travel must be completed by this time.
If the route shown on the ticket has a , the ticket includes the cost of travelling between certain London Stations (e.g. between Liverpool St and Paddington) by either London Underground, Docklands Light Railway (DLR) or First Capital Connect (Thameslink Route) services appropriate to the route of the journey being made.
More information about Travelling across London to connect with another National Rail service
Note: Tickets will only be accepted by London Underground and DLR on the date shown on the ticket (or last day of validity for return portions of Off-Peak Returns) and until 04:29 the following day. -*Other than to change trains, a break of journey at intermediate London Underground or DLR stations is NOT permitted.-*Travel restrictions do not apply on weekends and public holidays.
From National rail web site
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