Although you date the discussion to 1820, it actually started in 1810. In that year, the "Bullion Committee" submitted its Report from the Select Committee of the House of Commons on the High Price of Bullion to parliament. For a full text, see E. Cannan, Th paper pound, London 1919. The report created two camps.
Bullionists were led by contemporary economists with high name recognition, including Malthus and Ricardo. They deplored the inconvertibility of the pound (paper money). This was a consequence of the "Bank Restriction Act"of 1797, which forbade the Bank of England to issue any cash (paper money). The consequence of the Bank Restriction Act was the rise of the "country banker", small banking houses issuing their own paper money. This money was unacceptable outside a small circle around the issuing bank, making it inconvertible in fact. The Bank of England could and did discount commercial paper, thereby financing foreign trade and creating negotiable paper denominated in pounds that could be negotiated. The money creation of the BoE and the country bankers meant that paper pounds circulated at a discount.
The anti-bullionists were led by the BoE and included parties, such as country bankers, foreign traders and the government. The BoE liked its discounting business as "risk free" as long as the underlying parties were financially solid and disliked the risk of issuing notes that could be redeemed (Cannan p. 34). The country bankers had found a way to get rich quickly (or fail quickly) and didn't want it to be taken away. Foreign traders found that the pound rate on foreign exchanges was more favourable than gold (this was largely due to the BoE's fee policy). The motivation of the government does not become clear. My guess is that the government liked the possibility to extend the paper money supply quickly in times of war. Country bankers that went broke would have functioned as a counterweight, with the holders of defunct paper money paying the equivalent of a tax (an ex-propriation, if you will) to keep the money supply in check. Keep in mind that France had a larger population, a larger territory and popular support from those oppressed by royalists (until the French army started misbehaving even worse). Britain's key advantage was that it had paper pounds and France was restricted by the metallic Franc de Germinal.
I hadn't heard of the Ricardo bullion (had no time to follow your links yet.) In light of the above, it seems likely that the bullionists got it approved through parliament, since the BoE and the government would not have condoned it. Though the BoE, bound by law, had the bullion bars created, it would have done whatever it could not to issue them. That was probably not difficult, with gold being more expensive than paper pounds. They would have claimed that the Ricardo experiment had failed for "lack of demand" and would have stored the bars in their vaults, to be forgotten. When they were in fact forgotten, the form of the bars would no longer have mattered, so the BoE could leave them as they were or re-melt them.
The discussion was decided by parliament in favour of the bullionists in 1819 by the Act for the resumption of cash payments and the BoE's factual resumption of cash payments in 1821. Here Ricardo also played a role, proposing an "ingot exchange system" as an intermediate stage between inconvertibility and full convertibility. If the bars were meant for this stage, the answer to your question is that the intermediate stage never came into effect, because the balance sheet of the BoE improved quickly after Napoleon had been defeated. The cost of this improved position was high unemployment among de-mobilised and handicapped former soldiers, a high crime rate and a decades long spate of executions, revolting the population.
Peter
