John, photos of the clutch lever on my series 2 machine showing it in both positions. As you can see there is plenty of slack when it is engaged. Note wear in clutch and lever will affect where point of engagement is and if it will lock in that position.
The clutch should lock in the disengaged position, ie pulled up. This is essential to enable safe starting as there is no other way to stop the tines, one of the bad points of the design. The levers and locking mechanism do wear with time and age.
If you have the old belt any good belt supplier should be able to match it to a stock item. If you do not have the old belt it should be possible to obtain one of the correct size if youtake the machine to a belt supplier where they can measure pulleys etc to calculate size required.
Latest issue is in post and should arrive soon if it has not already arrived.
Now available to download from The Cultivator page, (paid up members only).