I was going to write pretty much all of this. The stretch from the pier to St.Peters is not very nice for a novice as the road surface is so poor and people insisting on parking on the cycle lane. Care needs to be taken around the gyratory (I could even suggest walking for 2 minutes before...
Just use a decent U-lock and not a £2.99 cable jobby and your bike will still be there. There are too many'eyes' about outside the ground even while the match is on for casual thieves to start smashing off something like a Kryptonite