Cash building up inside a company is a good problem to have, and an easy one to leave unattended. The question is what it should be doing.
Cash building up inside a profitable company is a good problem to have. It is also one of the most commonly ignored. It sits in the business account earning very little, while the owner assumes there is nothing to be done until some future exit.
Surplus cash left idle is a slow, quiet loss to inflation, and in some cases it can complicate the tax treatment of the company itself. Doing nothing is a decision, and usually not the best one.
There is rarely a single right answer, but the levers are well understood. Pension contributions from the company can be highly efficient and reduce the corporation tax bill. Some surplus can be invested rather than left on deposit, within a structure that suits the company's position. And a sensible working buffer should always stay in place for the business itself. The right mix depends on your plans for the company and for yourself.
The mistake is to treat the company balance sheet and your personal wealth as two separate worlds. For an owner, they are one financial life. The surplus-cash question is really a planning question: what is this money for, and is it working as hard as the rest of your wealth? That is a conversation worth having long before any thought of a sale.