Thanks for the replies. Having looked at the regs again I think I have worked it out! I’ve never been in the position before of having to keep track of hours, in 17 years of lorrying! 
In answer to Rog the 43 hrs was taken 23/24 Aug and before that there was a 46hr on the 18/19th, the 26 was taken 30/31st. So as long as I take a minimum 45 within 6 days I’m ok, and then pay back the 19 owed from the 26hr before the end of the next week, or bolt it on to that weeks rest.
The bit of info I was missing was that no more than 2 reduced consecutively.
What was also cofusing slightly was that before the 26off I had taken 23 3/4 hrs off. Now if I had started work 1/4 hr later it would have been 24 but then I would have taken a 26 the day after too so 3 reduced in a row, or would you count the 24 as a daily rest rather than weekly? 