The phone mast in Darwell Woods, which used to be Vodafone-only, now hosts the O2 network as well.
The O2 service supports 4G at up to 29Mb/s download 10Mb/s upload. If you can see the mast, you should get these speeds. If it is slightly out of view, then speeds will be lower.
This will benefit not only direct O2 customers, but also anyone on any of the following networks
… because all of these are “Virtual” operators who utilize the O2 network.
The mast continues to support Vodafone customers (including VOXI, Lebara Mobile, Adsa mobile, and Talkmobile).
The operators mentioned in this article are, therefore, likely to give a good signal if you are in sight of this mast.
Technical note: the mast also supports Airwave, which is used exclusively by the emergency services. 5G is not yet available.