Definitely recommend a share in something that interests you. The group members are important too - you need to be able to get on and have similar attitudes, for example towards maintenance and aircraft cleaning etc.
I wouldn't be flying now, if I hadn't been invited into a group just as I was finishing my PPL. Easy availability and low price flying are absolutely worth it.
I'd recommend keeping some funds back to cover emergency maintenance costs, if you're somewhat limited. So from £6k maybe spend a max of £5k on a share. That way you won't end up over stretching yourself. Plus bear in mind monthly costs, and annual costs that need to be budgeted for.
Enjoy!