Not wishing to be pedantic, but there is NO ATC at Elstree. The service there is INFORMATION (used to be RADIO and may occasionally still be so).
The AFISO in the tower has control of ground movements, and can only advise for activity in the air. He may well be trying to see what's going on out there, but it is the pilot's responsibility to check for taking off, landing and so on (hence the "at your discretion"). Because of the very heavy traffic levels (especially on nice weekends) and the odd, long, 4 mile straight in joins for landing, someone has to try and give some order to the proceedings. It doesn't always work, and a go around can be an expensive extra ten minutes in the air....... but you have to take the "advice" of Elstree Information as much as possible, else bedlam would ensue.
Given the difficult circumstances, the chaps in the "tower" do a good job. Those of us familiar with Elstree know that, at times, the INFORMATION service is bending into ATC, but it isn't actually Air Traffic Control! On the ground, the taxiways are narrow, planes are parked on each side, and one has to be careful.
Just my 2p worth.