Well there's us (
Cosham Concert - Portsmouth), Solent - Portsmouth, us, Chichester, us, Ocean Brass - Southampton, us, SWT Woodfalls & Woodfalls Concert - Salisbury/Southampton, us, loads of others, ooh yes... and US :lol: !!
Seriously, there's plenty of bands in the area, covering all standards and I reckon we'd all be glad of another cornet player. Accidental's advise about L&SC and SCABA is good, but you should check out the
Wessex association site too as most Hampshire bands are in the West of England area. There's also the excellent
IBEW whick has a list by county of UK brass bands (at least the ones with websites).
Good luck!!