Most places that you want to stop at you'll easily find something to which you can lock your bike. Hopefully it will be a designated cycle space, but if there's not one convenient then consider contacting your local borough ward councillor  because increasing cycle use is high on their agenda and it might be possible to add a new parking place. If we don't ask, we don't get :-)
Always lock your bike. Even if you'll only be a couple of minutes.
Surrey Police give plenty of good advice . And if your bike has come from us, we keep a note of the frame number (in case you've lost the sales tag which had it on) and we might still have a photo, so contact us.
The most common type of robust lock is a U-lock (or D-lock)  with which you can lock around your seat-tube and rear wheel, and to a bike stand. If you find that too bulky/heavy, then use a lighter type of lock, but do please still use one.