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Because that's when they orchestrated the first big merger in UK brewing. When they clubbed together with two other established London breweries to form Watney, Combe Reid.

But they were busy with other deals, too. Like taking over the Mortlake brewery, their final home.

"Messrs. Phillips, More, and Co., Limited, Mortlake Brewery, S.W., have completed the amalgamation of their company with that of Messrs. Watney and Co., Limited, Pimlico, and they trade now entirely under the style of Watney and Co., Limited. The business is conducted, however, in all respects precisely in the same manner, and under the same management, as hitherto."
"The Brewers' Journal, 1898", page 134.
The new merged company was enormous, with a combined output of over 1 million barrels a year. And a huge amount of share capital:

"Watney, Combe, Reid and Co., Limited — Registered, with a capital £9,000,000 in £1 shares (2,500,000 first preference and 6,500,000 ordinary), to adopt and carry into efiect three several agreements made by this company with Watney and Co., Limited, Combe and Co., Limited (and the liquidators thereof), and with Reid's Brewery Co., Limited (and its liquidators), for the acquisition of the businesses and undertakings, assets and liabilities, &c, of the said companies, and to develop and extend the same. The first directors — of whom there shall be not less than nine nor more than 15 — are Messrs. H. C. O. Bonsor, V. J. Watney, C. Combe, A. M. Wigram, C. J. Phillips, C. Watney, R. Combe, C. H. Babington, C. H. Combe, H. E. Phillips, J. A. Combe, 0. P. Serocold, E. M. Wigram, and P. Combe. Qualification, £8,000. Remuneration, £22,500 per annum, divisible. Registered office: Stag Brewery, Pimlico."
"The Brewers' Journal, 1898", page 536.
To put that into context, the same year Tetley was floated with a share capital of £1 million and Charrington, one of the largest breweries in London, with £3,950,000 capital.

Though there were still a few formalities, like vacuuming up all the stock of the three constituent companies and converting into stock in the new company:

"Watney, Combe, Reid and Company, Limited.
The statutory meeting was held at the Stag Brewery, Pimlico, on the 10th inst. Mr. H. Cosmo Bonsor, M.P., who presided, observed that nearly all the stockholders of the three companies which had recently been amalgamated had assented to the change and had converted their various stocks into the stock of the new company. In regard to the debentures, about 8 per cent. in money value had not yet been converted, but in view of the fact that a considerable quantity of the stock was held by trustees and others, an that a great deal of it was in joint names, he thought that the terms ofi'cred had been sufficiently liberal to bring in a large body of stockholders. In regard to the conversion of the old preference stocks of the companies the amount unconverted was so small that he could not place it in the form of percentage, but there were under 20 stockholders who had not as yet converted, and some of those had not given their assent owing to absence from England and other causes. This absence, of course, prevented these stockholders from completing their transfer. However, the directors could say that practically the whole of the preference shares of the old companies had been converted into the shares of the new company. The solicitors to the company had informed him that the application for a quotation and settlement on the Stock Exchange had been before the officials, and the directors daily expected to hear that both had been granted by the committee. The business, so far as the directors were aware, was doing as well as they could possibly expect."
"The Brewers' Journal, 1898", page 763.
Then came the inevitable closure of one of the three breweries:

"The Brewing operations of the amalgamated company of Watney, Combe, and Reid, Limited, will, in future, conducted, we understand, at Pimlico and Long Acre. We learn that it has been decided to close Messrs. Reid's establishment, or, at any rate, not to use it as a brewery, the other establishments being sufficient to meet the demands of the company's trade."
"The Brewers' Journal, 1898", page 820.
Combe's Long Acre brewery didn't remain in operation much longer. Presumably because Watney's two breweries in Pimlico and Mortlake had sufficient capacity. However, Watney continued to brand some beers Combe or Reid for decades.

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