B767 CREW HAD TRACK DEV DEPARTING EGLL ON THE WOBUN 2 (WOB 2F) SID.

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WE WERE DEPARTING LONDON HEATHROW ON THE WOBUN 2F (WOB 2F) SID. WHILE ON THE 301 DEG BEARING TOWARDS BUR NDB; THE NEXT TURN OCCURS AT 7 DME FROM THE LON VOR WHEN YOU INTERCEPT THE 360 DEG BEARING FROM BUR NDB. I WAS HAND FLYING THE AIRPLANE USING LNAV AT THE TIME. AT D7 LON; WE BEGAN THE R TURN AS THE SID DIRECTS TO INTERCEPT THE 360 DEG BEARING FROM BUR NDB. WITH A NORMAL RATE OF TURN FOLLOWING THE FLT DIRECTOR; THE TURN TOOK US A SMALL AMOUNT THROUGH THE COURSE TO THE W SO WE HAD TO CORRECT BACK NORTHEASTERLY TO INTERCEPT THE 360 DEG BEARING. LONDON CTL THEN GAVE US A VECTOR TO FLY HDG 015 DEGS. THIS SLIGHT FLY-THROUGH OF THE COURSE WAS NOT VERY SIGNIFICANT AT ALL; AND LONDON CTL NEVER INDICATED THERE WAS ANY PROB. THE REASON I WANTED TO RPT THIS WAS BECAUSE I KNOW THAT IT IS EXTREMELY IMPORTANT TO FOLLOW THESE SIDS PRECISELY. IN THIS SIT; THE TURN SHOULD PROBABLY COMMENCE A LITTLE PRIOR TO THE D7 LON; AND WIND COULD BE A FACTOR TOO. TAKING THESE THINGS INTO ACCOUNT; THE TURN COULD BE MADE TO ROLL OUT RIGHT ON THE 360 DEG BEARING FROM BUR NDB. IT SEEMS AS THOUGH THE LNAV WANTS TO BEGIN THE TURN R AT D7 LON; AND THIS COULD ROLL YOU OUT A LITTLE W OF COURSE DEPENDING ON WIND. PLANNING AHEAD AND KEEPING WIND AND YOUR SPD IN CONSIDERATION WILL HELP TO MAINTAIN THE PROPER SID ROUTING (TRACK). ONE THING I DID NOT MENTION PREVIOUSLY WAS THAT PRIOR TO D7 LON; LONDON CTL HAD GIVEN US AN UNRESTR SPD FOR THE CLB. THIS TOO CONTRIBUTED TO THE SLIGHT DRIFT-THROUGH.