Bilstein make a standard front strut for W124s in Europe / GB that performs like the stock version. I haven't seen a "comfort" version, although anything that softens the ride would be good on GB roads.
I would not cut a standard road spring down in length either: The ruined handling characteristics will bite you hard.
Strut mounts on W124s are just an aluminium stiffener with a rubber cushion and steel mounting plate. KYB make aftermarket versions for half the MB price. KYB are factory suppliers of suspension components to VW, Audi, etc, so, ought to be okay quality wise.