With no intent to start a row, or insult the OP, people that misuse a variation for 7.62mm/.308 are being too clever for their own good and that of the wider shooting community.
The applicant will know what was agreed when the variation request was submitted (like Heym would have agreed his 7mm variation to mean he would therefore be allowed to purchase any of 7x57, or 7x64 or 7mm-08) and that is what should be purchased when the then varied FAC returns back.
This "Well 7.62mm means I can get a .30-06 'cos its metric designation is 7.62x63", is childish and, frankly, disengenous. Simply, WHAT was asked for and WHAT was agreed?
An FEO tries to be accomodating so as to allow purchase of a .308W where, on some rifles, it may be stamped as a 7.62mm (think some P-Hale rifles) and that sensible accomodation is then misused to speculate on .30-06...what next? 7.62x54, 7.62x72 or in fact any nominal .30 calibre rifle given some bogus metric designation?
These ingenious abuses of FEOs trying to accomodate FAC holders are what feed the demand...in some police licensing authorities...for not just calibre be listed under an authority to acquire but specific make and serial number of the weapon.
It's a silly game. Stop it. If an applicant wants a .30-06 they should go back and request the variation be changed instead of using supposed or bogus or now long forgotten and so called metric designations. A .30-06 is a .30-06 and looking back to obscure references to it as 7.62x63 or .300 (as used by British Armed Forces in WWII) or .30 US G'ovt (as used also) is, as I've said, an abuse of an FEO's goodwill in trying to be accomodating.
For good our licensing system still works on a trust basis. That we are trusted to acquire what's been agreed. This "metric mischief" to acquire what may NEVER have been part of the discussion when the variation was requested and agreed to is an abuse of that trust.