Hi Zip, I have a similar issue to you in that I'm larger than average (6ft 7in and 18st) so settled for a Cube Aim 29 earlier this year. A big sturdy mountain bike felt much stronger than a hybrid, all I did was fit Schwalbe Silento tyres as most of my travel is on tarmac but they're perfectly fine for tracks and the like. I rode a Marin mountain bike for years and while it served me well it felt flimsy compared to the Cube.
From the look of this add they're available through Halfords cycle to work scheme now as well........
http://www.jccookcycles.co.uk/Cycle-to-Work-Scheme
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Audi D3 S8 - 2007 - V10. B&O, Phantom Black, black and silver interior, and still completely standard with everything working as it should
SOLD 2023
Audi TT - 2015 - Ultra