Advice for a newbie thinking of a 20 mile commute

[DaveE]

I think there are 3 main aspects to consider when choosing a bike for commuting: the bike needs to be fully equipped for all weather riding, easy and pleasant to be pedaled without power, the motor needs to be appropriate to your weight to give you a reasonable amount of torque on hills and the battery, which is as usual as big in capacity and as light as possible.
If you go for a conversion then it's easy to start with a reasonably high end bike but esthetically, the electrics does not usually 'hang' well with the bike and the wiring is much more exposed to rain water than a factory built bike.
If you go for a factory built bike, then for your weight, you will need a high performance bike rather than a run of the mill one. Most of them start at around £2k.
That leaves just one candidate (beside the Woosh bikes ) for your budget, the Greenway with the Bafang MaxDrive is worth a look.

I would love to get a Woosh if it was possible under my work's scheme. Sadly I don't think it is.