Hi lighting Phil. Much faster. My FTP is up from 225 to 275, haven't lost an ounce though.
I use a Wattbike twice a week, just using their own platform and usually an 84 minute interval session or an hour interval session. It's super reliable, and doesn't need calibrating in the way that a tyre on a roller does, so it's a very accurate way of measuring performance. I'm not so focused on Watts per kilo, more Watts per heartrate. Once a month I carry out a 20 minute FTP test and the Wattbike adjusts the workouts to suit current fitness.
I did briefly try Zwift, but it's not for me, the noise, the cheating. Each to their own. When on the Wattbike I focus on heartrate and perceived effort.
I try to fit in a 70 miler weekly , Letchworth to Thaxted loop , lumpy nice countryside.
I think you must live not far from me. If you want a training partner perhaps we could arrange something. Cheers Andy