Until your scars have fully matured (6-12 months), any form of ultraviolet energy can turn scars brown (and unlike tanned skin, this brown scar discoloration does NOT fade over time).
I know you don't want to burn on holiday, but tanning before you go is a bit like taking small doses of rat poison daily so when you take a big dose of rat poison it won't kill you! Ultraviolet energy causes skin cancer, wrinkles, and causes the pigmentation issues with "not-yet-mature" scars discussed above.
Don't get me wrong--I like the "bronzed beauty" look as much as you do, but the way to do this SAFELY is with mist or spray tans that give you the color you want, and then the highest SPF sunblock that you can find that your skin tolerates.
That way you can not only have that beautiful "tanned look," but you will protect your skin (and your scars) from the harmful effects of ultraviolet radiation! And not just on vacation, but always. You will thank me for this advice in another decade or two!
(BTW, I know you need sun for Vitamin D synthesis; 15 minutes a day is sufficient for all the Vitamin D you need. Or, you can just take a daily multi-vitamin or drink a glass of milk, which has Vitamin D included!)