We want details!
Nothing too esoteric, just relentless and skillful combined use of maritime bombers, subs and surface vessels, matched against my lack of maritime bombers and imprudent use of the RN's large but not inexhaustible supply of surface vessels to support overstretched commitments in vulnerable theaters.
Not really following - Germans have 1 maritime bomber so what do you mean bombers? I'd be interested in play-by-play - where you attacked in North Sea? Did you use French fleet to counter? etc.
GE and IT MBs.
I did not aggressively use the French fleet until after it became clear that Fafnir was going for all of France, as I thought it more important to bolster French NM than to save a few expendable RN CAs.
There was a sort of slow plunking, here and there, which slowly whittled my strength down, mostly killing CAs, CLs and CCs, which I was using for recon and covering other more valuable assets. A few were dispatched in the Channel, a few in the southern Atlantic, etc. In addition, there were two large engagements, one west of the Bay of Biscay and one in the western Med and around Gibraltar, both of which ended poorly for the RN. The first involved a large-scale raid from the Channel ports on north-south traffic from the UK. That one could have ended even more poorly - Fafnir's subs were sniffing around and sunk several vessels but missed a CV by one hex. The second resulted from my efforts to resupply Egypt and put some hurtin' on the IT BBs in the Med. I hit an IT BB in Marseilles with a CV but took a lot of damage to the air wing from a GE FTR, then retired to hide off Barcelona. Unfortunately Fafnir's MBs in Algeria found me and took each of my CVs down to ~6 strength and the Regia Marina sunk several covering vessels. The French fleet was covering for the RN, and took some damage, but my sense was that Fafnir was focusing on RN vessels. I then retired to the Gib area to cover several transports bound for Egypt (an AT, an army and a corps). Next turn, Fafnir took Oran and most of the French vessels disappeared. I then tried a desperation dash to Alexandria with the transports, with a sub partially clearing the way, but it was my hopes that were dashed when my AT and army went to the bottom around Sicily. Fafnir then closed the escape hatch with subs and the Kriegsmarine west of Gibraltar, sinking several vessels that were bidding to escape the slaughter. By the end I had all of my BBs, most of my CVs and several DDs, but had lost most everything else (including one sub with the second about to join it at the bottom of the Med).
As a result, the ITs ruled the Med (and the Axis were likely to take Gib in a few turns after bribing Franco to join), and GE subs and surface vessels lurked everywhere from the Indian Ocean to the north Atlantic. The RN would have been confined to port until I had obtained a few levels of anti-sub and built a few MBs to recon the approaches to the UK, at the risk of losing critical assets like my remaining CVs. The UK was effectively sidelined, and likely would have been further marginalized attempting to defend the Murmansk convoy line following the kickoff of Barbarossa.
Some lessons: as the UK, don't stint on anti-sub and anti-air research, don't overcommit to France, and don't use CAs and CLs as if they were expendable, because if you do you may just run out.