Supplementary Indications
BWMA
Here is an excerpt of statutory instrument 3046 (our emphasis):
The Secretary of State, being a Minister designated
(a) for the purposes of section 2(2) of the European Communities Act 1972 (b) in relation to units of measurement to be used for economic, health, safety, or administrative purposes, in exercise of the powers conferred by that subsection, makes the following Regulations:
...3 - (1) In section 8(5A) of the Weights and Measures Act 1985 (d)(which allows the use for trade of supplementary indications up to and including 31 December 2009), omit "up to and including 31 December 2009".

The government is nullifying the Weights and Measures Act 1985, in so far as it applies to supplementary indications, by way of a statutory instrument passed under the 1972 Act.  This is the same technique that outlawed imperial units for use in trade, leading to the conviction of Steven Thoburn and other traders.  Repealing or negating an Act of Parliament by an older Act goes against British constitutional law which requires that, when incompatibility exists, the latter Act takes precedence.  Clearly, there is incompatibility caused by statutory instrument 3046: the 1985 Act (as is) renders supplementary indications illegal; the 1972 Act makes them legal.

The government's use of the 1972 Act is surprising given that, having outlawed imperial units in this way, it realized subsequently that the same principle also endangered Acts designed to impose government fines outside of the courts.  A letter from the Home Office in November 2006 backtracks: "If, and to the extent that, a modern statute clearly provides for such penalties, it is a necessary implication that any provision in any earlier enactment to contrary effect does not apply.  Courts and tribunals are obliged to implement the modern statute".

Since 2002, therefore, we have switched from implied repeal (which, up until that point, had lasted for centuries); to a hierarchy of acts, to protect Britain's implementation of the EC metrication directive and, by implication, Britain's membership of the EU; back to implied repeal, to maintain the government's power to seize private money and property without allowing affected parties appeal to the courts; and now back to the hierarchy of acts, to preserve the European Union's export trade.  All of which suggests that the rule of law in Britain is permanently broken.

Readers with an internet connection whp wish to inspect the atutory instruments may do so at these locations:
http://www.opsi.gov.uk/si/si2009/uksi_20093045_en_1
http://www.opsi.gov.uk/si/si2009/uksi_20093046_en_1

Reply from Peter Mason, Chief Executive, National Measurement Office, to BWMA letter of 24 August 2009:

Last issue recorded our letter of 24 August to Peter Mason, Chief Executive of National Measurement Office, Teddington, Middlesex; and extract is produced here for convenience:

Dear Mr Mason
... I draw your attention to paragraph three on page two of the [government's] 2005 letter.

     "As for the much smaller physical trade in precious metals, this can be conducted in either troy or metric units, whichever the purchaser and seller find convenient.  We would thus suggest that the continued use of the troy ounce in these contexts is not in practice a barrier to trade between Member States".

You will be aware that the above practice has not been applied to pounds and ounces for foods, etc.  It has been the government's view for a number of years that one authorised set of measurements is needed for consumer protection, as illustrated by this statement from 1996:

     "It was considered that if some products were sold in imperial units and others in metric, this would hinder the consumer's ability to make value-for-money comparisons, and would open up the scope for fradulent trading".

... We would be grateful if you could explain this contradiction

Mr Mason's reply, 6 October 2009:

"Thank you for your letter dated 24 AUgust concerning a reference to the trade in precious metals in the Government's letter of 14 December 2005 to the European Commission.  I am sorry for the delay in replying.  I can confirm that the Government's view remains that a single system of measurement is necessary of ensuring consumer protection.

"With reference to the comments you highlight in the 2005 letter, I should point out that the trade in precious metals mentioned in the text of the letter referes to a trade which take place predominantly between Members of the London Bullion Market Assocoation, that is to say major international banks, and where transactions are often across borders.  In this case we would not regard consumer protection as a determing factor.  However, you may be interested to note that the vast majority of those transactions use the troy ounce.  I hope this is helpful".

Analysis
The key word in Mr Masons' letter is presominantly.  This means that not all gold trade is at the international level, and that some is at an individual level.  A search on Ebay at any one time reveals thousands of auctions for gold chains and bullions coins, to say nothing of 'cash for gold' dealers.  An equivalent argument might be that as the vast majority of oil is purchased in tankers by governments and corporations, consumer protection is not needed when selling to the motorist at the pump.