Starter motor refit issues

I removed a starter motor (an old Valeo model) from a 1987 90 2.5 TD. I have been assured that the replacement (a Lucas model) will fit. However, I can't get the screw holes to line up (I believe that part of the starter motor unit is preventing me from turning the s. motor sufficiently to line up since it presses up against another part of the engine).

Now, I may be a complete gonzo about this but, am I doing anything wrong?

Is it worth taking the motor apart to fit it in two (careful) pieces?

Help!

If you take it apart it will be near impossible to reset the brushes in-situ.

have you compared both side by side?

also, try moving the starting gear cog thingy back. if its thrown out, it may be contacting the flywheel, preventing it going in.

G