Personally, I broke even moving to the hourly rate. My basic pay went up by around 5%.
Very few pilots saw their basic pay go up by anything like 20% to be honest. The ones who did best from the deal were junior Captains who had historically been significantly underpaid to that point. The proof being senior longhaul co-pilots who, when the allowances were being taken into account, were taking home more than junior Captains on the same fleet. There was no incentive either for these people to bid for shorthaul commands as that would also have meant a pay cut, particularly moving down to LGW. Now, you will not find a Captain who takes home less than a co-pilot on the same fleet and LGW pilots on the same deal as LHR pilots, albeit with a pay cap. Overall, a forward step IMHO.