The TR engined +4s can run quite hot , so fan-assisted cooling is good idea.
The standard engine driven fan was never up to much anyway , so don't have any concerns about running without it.
As others have said do not put a fan in front of the radiator, it hinders air flow and stops cooling (the hindrance is proportional to the square of the area of the fan and brackets)
The "puller" type fans are much better in this respect , yes they do hinder the air exiting the radiator , but not to the same extent.
I would personally go with the SPAL , but others are available. Your radiator may already have the brackets in place, which makes fitment much easier, if not I am sure Peter Mulberry will oblige.
Regarding electrical installation the fan is a high current item, and the early +4s had very little in the way of electrical circuit protection. Be sure to fit both a relay and a fuse it. Although normally controlled automatically by an "otter" switch , some folk recommend a manual override in addition to the auto system. This is easy to install when you do the fitment, it is also a useful check to ensure the fan is working.
