We're getting to the mid-point of the Formula One calendar and the tweaks, additions, new aero parts, rumours of driver line-ups for next year are coming thick and fast.

Aero tweaks are the most obvious adjustments to a car's performance - oft discussed new noses and front ends fill column inches.

Ferrari's early season addition of wing mirrors to the safety Halo brought out waggling fingers from the FIA and clarification on what was permitted, and what wasn't.

F1 teams are renowned masters of interpreting technical directives, and then exploiting loop holes to gain advantage. 

Ferrari tried it on for the Spanish Grand Prix and failed. 

But, while techical scrutineers may miss an adjustment here or there, rival teams don't miss a trick. 

Mercedes is the most recent team to add structural supports to their wing mirror array, prompting questions of legality from other teams on the grid. And while Ferrari's mirror enhancement did not find acceptance with the FIA, it appears Mercedes have adhered to the rules. Precisely.

The FIA is more than satisfied with the German teams technical addition stating that their new mirror designs comply 'to the letter' - despite rumblings from the paddock during the Austrian GP.

The wing mirror improvements were part of a complex series of new bodywork components brought to the Red Bull Ring, with the mirror struts designed to support the existing mirror set up.

Ferrari's early season transgression had been suspected of gaining them an aero advantage by tweaks to the mirrors halo mount.

Talk along pit-lane was that the additional Mercedes mirror supports were not to aid stability, but designed to improve handling. 

Charlie Whiting, F1's unflappable race director, was aware that teams were questioning the enhanced bodywork, but has concluded that the technical rules have been followed correctly. 

"We are happy with them because they conform precisely to the letter of the TD [technical directive] that we sent," he said.

"The additional mounting is on the underside of the mirror, so I don't see any issue there at all. If you look at the Force India and the Red Bull they have something similar, but not so far outbound."

The technical directive Whiting refers to was issued as clarification after the launch of Ferrari's new kit at the Spanish Grand Prix. 

The early season technical directive was quite clear, although as seen over the decades, all  advisories are open to interpretation.

In the TD, the FIA stated: "Whilst we accept that teams will legitimately design the mirrors, housings and mountings to minimise any negative aerodynamic effects they may cause, we believe that any aerodynamic benefits should be incidental, or at least minimal.

"While the extent of an "incidental" benefit is open to interpretation, it is important to note that Tombazis made it clear that any support should be: "mounted to the lower and/or inboard surface(s) of the mirror housing."

So that's all good then. Bring on Silverstone.

Let's hope the 27-degree race day temperatures forecast for Silverstone's British Grand Prix bring fast, open and exciting racing.

Overtaking should not be an issue and the former aerodrome's long Hangar straight, sweeping Beckett's bends and lightening fast Copse corner will be something to look forward to.

For drivers and fans alike.