Hopefully that might be a possible solution! Currently, as my Imperial otherwise works perfectly and I use it daily, I've had to make-do with fashioning a reinforced handle by positioning two metal strips around the broken area and bolting them together. It doesn't look as bad as I feared it would (rather the new metal and bolts blend quite well). Thankfully with the Imperial being near and dear to my heart as my first typewriter, I've no intention to ever sell it but I'd like to retain a look as close to how it was originally.

Your machine was made in Portugal by a firm called 'Messa' on Imperial's behalf circa late 1960's/early 1970's.  Unfortunately the 2002 does not bear any resemblance to any other machine and the line space lever is unique.  Being composite metal and plastic, breakages were quite common.  I did have just ONE brand-new lever left, but when I traded in another 2002 with just the stub of a lever left, I fitted it to that machine.  It is now the typewriter that I loan to customers when theirs is being repaired.  If it is any consolation to you, fitting the lever is a cussedly awkward job.  As you say that you are not a D-I-Yer, with all due respect I don't think that you would have been able to manage it.  Probably the best repair would be to do as you have already done and attach a metal extension to the stub.  The 2002 isn't a particularly good typewriter in any case, although I do not deny that it does type and seems to do the job.