If you Google the actual address you get a listing of all Companies registered at 15-19 Bloomsbury Way, London. It is the main Office of BUPA international as well as the registered address of the following companies below.

If you have had an offer from one of the below listed than it will be ok, if the company that wrote to you is not named here I would be extremely cautious.

These are the Google search results on Google Maps.
All businesses at Bupa House, 15-19 Bloomsbury Way, Camden, London WC1A 2BA, UK
Categories: Health Insurance
Bupa‎ - more info »
15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 0800 600 500‎ - 0.1 mi N
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M Spencer Swaine Ltd‎ - more info »
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7623 0023‎ - 0.1 mi N
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British United Provident Association Limited(The)‎ - more info »
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7506 2000‎ - 0.1 mi N
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Bupa Australian Finance No.2 Ltd‎ - more info »
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7656 2000‎ - 0.1 mi N
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BUPA Hospital‎ - more info »
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7506 2000‎ - 0.1 mi N
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Bupa Health Assurance Ltd‎ - more info »
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7506 2000‎ - 0.1 mi N
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Bupa Finance plc‎ - more info »
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7656 2000‎ - 0.1 mi N
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Bupa Europe Finance Ltd‎ - more info »
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7656 2000‎ - 0.1 mi N
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BHSL Properties Ltd‎ - more info »
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7656 2000‎ - 0.1 mi N
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Bupa International Insurance Services Ltd‎ - more info »
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7506 2000‎ - 0.1 mi N
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A.Bupa
15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 0800 600 500‎ - 0.1 mi N
B.M Spencer Swaine Ltd
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7623 0023‎ - 0.1 mi N
C.British United Provident Association Limited(The)
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7506 2000‎ - 0.1 mi N
D.Bupa Australian Finance No.2 Ltd
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7656 2000‎ - 0.1 mi N
E.BUPA Hospital
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7506 2000‎ - 0.1 mi N
F.Bupa Health Assurance Ltd
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7506 2000‎ - 0.1 mi N
G.Bupa Finance plc
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7656 2000‎ - 0.1 mi N
H.Bupa Europe Finance Ltd
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7656 2000‎ - 0.1 mi N
I.BHSL Properties Ltd
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7656 2000‎ - 0.1 mi N
J.Bupa International Insurance Services Ltd
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7506 2000‎ - 0.1 mi N
Bupa Occupational Health Ltd‎ - more info »
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7506 2000‎ - 0.1 mi N

BHS Leasing (1994) Ltd.‎ - more info »
15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7656 2000‎ - 0.1 mi N
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Bupa Gatwick Park Properties Ltd‎ - more info »
Bupa House, 15-19 Bloomsbury Way, London, WC1A 2BA, United Kingdom‎ - 020 7506 2000‎ - 0.1 mi N
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