Law was changed at the end of last year. Now your last break MUST be 30 minutes or more. If you drive for an hour, have a 30 minute break then drive for 3 1/2 hours, you must have another 30 minute break to cover your 45 minute total as your last break must be at least 30 minutes..
don't fprget it is not just drivers hours you need to think of its also the working time directive (wtd).
The WTD says all workers must show a 30 min brake after 6hrs work and 45min brake after 9hrs. these can be taken in 15min slots and can go towards your tacho brakes.
The wtd also states you can'nt work more than a 10hr shift if you start between 00.00 and 04.00. As far as i am aware no body has been prosecuted yet but the hse are starting to get heavily involved in transport and i think they will be hot on this. You will probably find you will get done and so will your company. There was a case in this country where a factory worker worked an 80hr week and killed someone on their way home he was prosecuted and his boss was done under coperate law for allowing him to work it and drive home. I have also heard this year and in the future sales men will be targeted on this because of the silly hours they spend on the road.