When I used to do City Council contracts, I employed part timers only. Different employment laws and costs here but it was worth it. Was doing hospitals and schools mostly. window after bloody window

Old experienced guys who were good for about 5 or 6 hours mostly, after that you start to get sloppy and make mistakes on the glass and H&S.
A certain amount of stress involved because of deadlines and access, but if you are keen and ambitious, then OK for those guys that are looking to build a good biz.
For Dom work, we try to do everything ourselves, (me and Mrs Cozy) as we have built our dom work on personal contact and wouldn't trust any Germans with it. Long story that.
If we employ someone full time here, it's a bloody trap. Full sick pay from day 1, holliday pay, Christmas bonus etc etc.
I can't see a problem with part time employing in the UK from what I've seen from the guys on here.