I shouldn't think there is any need to remove the rad...the Official procedure is to fit a tool (basically it allows the seal to slide over the crank shaft and seat into the front cover) to the crank shaft when refitting the front seal, never seen this tool so I don't know how long it is or if you could get it onto the crankshaft end with the rad in place...but from what I have read, it is not necessary to use this tool as long as when you fit the seal you keep it square and straight.
If your were to withdraw the camshaft then yes rad comes out...but you can fit the new front cover seal without having to remove the front cover...it is just a bit more fiddly to keep the new seal square on refitment.
As for the crank bolt being solid and no special tool...I have seen peeps drop the sump and using a block of wood (has to be wood as it is softer) wedge the crank from turning (pic attached). Never used this method and as long as you are careful it should be OK, but there could be a very remote chance of cracking the crankcase...but it is rather remote!
I will clean up my Crank Pulley and measure the holes and sketch out the PCD and sizes etc in case others want to fabricate there own Crank Pulley holding tool similar to the LR tool.
