You don't need to ride all the events - simply turn up in good time with an old mountain bike or racer with knobbly tyres and don't wear white! Circuits are usually around a park or woodland and you won't get lost or dropped - although you might get lapped; but there's no shame in that as by then, no one really knows who the leaders are! For more info:
The two local websites are www.cxne.org.uk and www.neccl.co.uk. See you there.