Some one is sure to correct me if I'm wrong, but if my memory serves me
right there is a plate covering the peephole to the flywheel.

Certainly the case on the 6 pot 2.6 and I think the same on the 4 pot.

Lee D

If it has the original engine, there will (should)  be a three pronged
pointer above the crankshaft pulley, pointing to a notch in the pulley. The
three points are TDC, 3 & 6 BTDC.
If it has an early 2.25 engine there is removeable cover on the top right of
the flywheel housing with a pointer and the marks TDC, 3 & 6 on the
flywheel.
In both cases the marks are designed for static setting of the timing, not
using a xenon light.
The timing setting will depend on the type of fuel being used and whether
you have a 7 or 8 compression head, but probably 3 BTDC static.
JD

You can't use a Xenon strobe light timing gun on a 2.25 petrol. The
timing marks on the earlier engines are on the flywheel. There's a
little access plate at the back of the engine, on the flywheel housing
- on the nearside.

2.25's have the timing set staticly. You move the crank to the desired
timing mark on the flywheel, and adjust the distributor using a lamp
connected across the points. The procedure is detailed in both the
haynes and LR workshop manual.

Alex