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Avoid all MacBooks.
http://buyersguide.macrumors.com/#Mac
They're all due a refresh in the coming months / end of year, and as such all of the specs are way out of date and you won't be getting decent value for money.
But for a real workstation load... afraid that you do need a workstation. The Lenovo P50 is really nice, but I appreciate it's not for everyone. Workstations are large, heavy, produce a lot of noise and heat.
http://www.apple.com/uk/shop/buy-mac/macbook-pro?afid=p238%7CsIuNqkIGk-dc_mtid_187079nc38483_pcrid_64626336601_&cid=aos-uk-kwgo-pla-mac-slid--product-MJLT2B/A-UK