I've got mine in bits too Simon. It's done 18 years and 28,000 miles since the last rebuild...
I use semi-fluid grease too. I used Penrite for many years but now use Morris oils for everything. British y'know!
In addition to what others have written I would say that the two bushes in the fourth gear didn't stick with Loctite when I used it 18 years ago! It's just my opinion but I think Loctite doesn't work when it's submerged in petrol or oily environments. I soaked my driving gear and new bushes in alcohol before assembly to get them clean. Perhaps they lasted awhile...
Check your selector forks, especially 4th gear... And do remove the split pins from the selectors and check the sliding dowels don't have flats on them in the slots in the camshaft.
The other thing I would say is on the timing of the quadrant and camshaft on reassembly. The book implies that you should rebuild in neutral and time the two 0's together. But this is NOT neutral... It is a false neutral between second and third gear. I annotated my Waller thus after scratching my head for awhile and finally thinking about it all. If you think that the quadrant moves up and down between 1st and 4th, then it's pretty obvious that the position of the 0's at half way along the teeth must be halfway around the camshafts rotation.
Going anticlockwise the 0 on the cam gear is at about 2 o'clock in 4th, 11 o'clock in 3rd, 8 o'clock in 2nd, between 5 & 6 in detented neutral, and about 4 o'clock in 1st. You can find an undetented neutral between 2nd and 3rd, and 3rd and 4th. The 0's align in undetented neutral between 2nd and 3rd.
And another thing... You will by now have discovered that the only way to change a gearbox (drive chain) sprocket on a BA box is to strip the whole box. Full marks to the designer! Burman got it better with the GB box... If your gearbox sprocket, an item prone to wear what with sloppy chains and road grit, looks even slightly dodgy, do yourself a big favour and put a new one on, rather than unnecessarily stripping the box for no other reason.
(AOMCC Exec Committee & Selly Oak branch rep)
'47VB, '51KH, '58FH, '05 BMW oilhead boxer.