Not Belgium, Bulgaria, Czech Republic,.... Baroness Neville Rolfe
Belgium, Bulgaria, Czech Republic, Denmark, Estonia, Finland, Great Britain, Ireland, Latvia, Luxembourg, Lithuania, Poland, Slovenia and Sweden... did not write a letter. These things are usually done by a single lobbyist who then farms it around for signatures.
So in Britains case they got the 'Baroness for Life' Neville Rolfe (think 10 years in jail for copyright infringement Baroness, the ex Tescos exec ), to sign the letter.
Does she speak on behalf of Britain? No. Does she speak on behalf of the government? No, she's bottom tier government, she sounds like she's trying to take Ed Vaizey MP's role. It's his portfolio, not hers. Doing that "pretending to be the boss as a means to become the boss" trick, perhaps*.
Data Retention Directive, was pushed through by Tony Blair when the UK had the EU Presidency. It's been ruled illegal in Germany, the EU legal opinion is probably correct. You can't bulk spy on innocent people on the assumption they will be criminals in future. That was very much a Tony Blair (in his Bush persona) thing.
I don't see how requiring companies track their users as "presumptive future criminals", is a digital markets issue at all. It's a fundamental rights issue, way above the micro business regulation of the internet. They are required to obey the fundamental rights, they don't get to waive them away as part of minor regulations.
* By signing this letter, the reply, and the discussion around it goes to her, instead of Ed Vaizey, and so she usurps the Communications role and her opinion is heard over Vaizeys as though its her role.