Complex sentence: In the late BR period, drivers received a fairly low basic salary of around £12,000 p.a., supplemented by an extremely complicated series of enhancements for overtime, thus many drivers had to work Sundays in order to make a good income.
Split into simpler sentences: In the late BR period, drivers received a fairly low basic salary of around £12,000 per annum, supplemented by an extremely complicated series of enhancements for overtime. Thus many drivers had to work Sundays in order to make a good income.