Today I’ll be examining the long-term investment appeal of paving specialist Marshalls and door and window components supplier Tyman. Could these lesser-known London-listed companies really make you rich, or will the impact of Brexit put a halt to their growth prospects?

2020 vision

Mid-cap paving specialist Marshalls (LSE: MSLH) reported a solid first half to its trading year when it updated the market with its interim results for the six months to the end of June. Revenue was up 2% to £202.4m from £199.1m for the same period a year earlier, with pre-tax profits leaping to £25.1m, a 21% improvement on the £20.8m reported for the first half of 2015. As a result, management declared an interim dividend of 2.90p, 29% higher than the 2.25p paid out the previous year.

The Halifax-based company continues to press ahead with its 2020 Strategy to grow the business organically and selectively through acquisitions. The strategy is driven by a focus on innovation and new product development with the aim of extending the product range and providing more integrated solutions to improve the customer experience and differentiate the Marshalls brand.

Brokers expect Marshall’s underlying earnings to reach £40.65m by the end of next year, leaving the shares trading on an attractive price-to-earnings ratio of 15 for 2017. With the shares losing a fifth of their value over the last 12 months, now could be a good time to buy for both capital growth and improving income.

Optimistic outlook

Door and window components supplier  Tyman (LSE: TYMN) also achieved a strong first half performance as it continued to make improvements to margins. Pre-tax profits for the period January to June rose from £7.7m to £7.8m, with revenues 15% higher at £201m, compared to £175.4m reported for the same period a year earlier. As a result, management raised the interim dividend to 3p per share, 13% higher than the 2.66p declared for the first half of 2015.

The small-cap firm said its strong performance in the US was aided by year-on-year growth in new build permits and single-family homes, although conditions in the Canadian residential market continued to be challenging. There was also continued improvement in Europe and the Middle East, helped by a contribution from Italian aluminium windows and doors manufacturer Giesse, which it acquired in March for €78.9m.

City analysts share my optimistic outlook for the company, with consensus forecasts predicting an 11% rise in earnings for the full year to December, followed by an even better 14% improvement in 2017. The shares look excellent value trading on a forward price-to-earnings ratio of just 12, and supporting a prospective dividend yield of 3.7% for 2017. In my opinion both Marshalls and Tyman remain well positioned to see off the long-term effects of Brexit and continue to make progress in their respective niche markets.

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Bilaal Mohamed has no position in any shares mentioned. The Motley Fool UK has recommended Marshalls. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.