Congrats on your purchase ??.
Bird poo removal is a matter of starting weak and getting stronger until it eventually goes.
1. First try water spot spot remover (like 50/50 white vinegar/water).
2. Try a hand polish with Autoglym SRP (Super Resin Polish).
3. Using a machine polisher with 3" pads and a cutting compound gently go over the area and repeatedely buff off the polish to see if it's gone. Repeat as necesssary if progress is made.
4. Failing that I have wet sanded the area with 2500 wet sanding paper with gently straight line movements followed by step 3 to bring back the shine of the paint and Step 2 to refine the finish to a nice glossy black finish. Then give them some protection - spray sealant etc...
The longer it's been there in hot sun the more it can etch the paint.
For future bird poo incidents have some MF cloths and detailing spray in the boot to wipe off asap - soak any dried on bits by placing a damp MF cloth or kitchen roll over the poo for about 15 minutes to soften it up.