I know. I can read. It doesn't matter whether it's turnover or profit. No one should stay at a company that's doing that much business with so few people without being paid more than that salary. Even if the company is making a loss then being paid £60k in a company with a £15m turnover is truly terrible. £15m is either a huge amount of work, in which case £60k isn't enough, or it's a reasonable amount of very expensive work, in which case £60k isn't enough.

The profitability of the company that you work for should have absolutely no impact on your salary if it's not making a profit. Do not accept less money for the value you generate just because the company can't sell it at a good price that makes a healthy profit. Your earning potential is not dictated by someone else's ability to sell.