We've been on lots of £26 breaks with Travelodge (just returned from 2 nights at London Covent Garden - have also been to London Royal Scot, York and Newcastle) without any problems.
You should be ok so long as you can check-in early. Basically Travelodge can (that's CAN, not necessarily DO) overbook on the same principal as plane flights are overbooked - on the basis that some people who have booked will not turn up. Rooms are then allocated on a first come first served basis so there is a possibilty that a late night/early morning check-in might find no room.
Therefore I wouldn't risk booking a Travelodge for a late check-in somewhere where other nearby Travelodges are not an option, but if you can arrive to check in reasonably early (3pm is normally the earliest) then you will have no problems whatsoever.