The simple answer to your question has to be 'No'.
All drivers are expected to read the traffic signs they encounter on their journeys. Every bus lane is clearly marked with appropriate signs. Some bus lanes only operate during certain hours but, unless specific times are shown, other vehicles are prohibited at all times.
If you failed to spot a 'No Entry' sign, and drove the wrong way down a street, you couldn't expect your lack of familiarity with the area to provide a valid defence. Similarly, I couldn't expect a be able to breach motorway rules just because I live at leat 50 miles away from the nearest motorway.
Bus lanes are clearly explained in the Highway Code which, although it doesn't directly have legal standing, is something which all drivers are expected to be familiar with:
http://www.highwaycode.gov.uk/11.htm#120
Chris