Many of us have placed UK street lamps on our UK routes, but there are many types; concrete, wooden, steel etc.
It would also be useful to know what period you are modelling. The modern smartposts are vastly different to the stuff that was around in the steam era.
Photos will be a great way of illustrating what you are looking for. There are loads on the DLS, but are not always easy to find because of they way some have been named.
Show us what you're after and I'm sure someone will come up with a good, or possibly perfect, match.
Do a DLS search for street lamp. That will find quite a few.
There may also be some which are more obscurely described, to which others may give you links. For example I use one which is a platform lamp, but looks quite a lot like the newer type of UK street light. It's called Lampadaire quai 02 - Platform Light 02 kuid:64819:28123
Here's how it looks in daylight. It has a ground light pool at night.: