Two pension schemes?

There are no rules against belonging to multiple pension schemes. In fact its probably the best thing to diversify your pension provisions. e.g. As you probably know, you can have an occupational pension and a state pension.

There are rules around how much you can contribute to a pension scheme. If memory serves, this year its up to £50,000 per year, and a lifetime limit to the pension pot of £1.8M

and....

But it is the DM

Flop

They are limits on what gets tax concessions, not absolute limits.

Yesss, but... when ordinary mortals (ie not bankers) talk about pensions they mean the government concession scheme that has a tax advantage.

Saving in a pension pot beyond the maximum tax free level makes no sense financially - far better to save in normal investment vehicles, such as savings accounts, gold bricks, fast cars, fine wine, bricks and mortar, or whatever you fancy. The saved money is yours to pass on to your estate / Battersea dogs home / HMRC or whoever you choose in your Will, or spend whoever you like at any time.

The banker in the DM is on a fantastic final salary pension. As far as ordinary mortals are concerned, this is an "indexed linked copper guaranteed bottomed salary for life". I doubt this was what the OP was asking about. The DM has calculated an equivalent figure for the cash pot which would generate such a Croesus-like "pension" and come up with 13M- odd. The lucky banker did not receive 13M-odd in cash as a pension, he got a fat-cat salary for life. He gets the equivalent of a Lotto win every year, for life, and no wonder he's smiling in the DM photo!