I'm not sure how long personalised rego plates will be an addition to a loved or cherished car. The current authorities in nsw, (the relevant govt dept seems to change its name regularly) seems to think it's a great money spinner, & the annual "donation" (in addition to your renewal) for personalised plates is from $100 up to somewhere around $450 pa.
I have 2 vehicles on "club" rego @ $46 a year, & with that comes special (somewhat ugly) rego plates. The stigma of the club plates is easy to overcome the more the cost of personalised plates goes up.
I have 3 sets of personalised plates (one set I have had for almost 40 years, so there is no annual cost on those) but they will probably go as I get more vehicles registered. Currently have 7 regos, & it all adds up!
I presume other states are similar, although I know in QLD, you can put your own personalised plates on club regd cars
End of whinge! & good luck for the sale