UPDATE!!!!!!!!
OK so we went to seek legal Profeesional Advice. We now have and HR team to deal with these issues. Out sourced of course!
OK each situation is different! So if it happens to you, you must seek legal advice just to be sure.
If you take on a contract with existing staff, and you have a workforce in place you can make those staff that are included in the transfer redundant! You must follow all reduncy policys.
If you take on existing staff you can change the days worked and hours but not pay, you cannot increase or decrease the hours, but you can move the hours to suit your requirements.
Give plenty of notice in writting to cover yourselves and explain it clearly in the letters.
Hope this helps others... but again seek legal advice like we did! Yes it will cost you money... but wont cost you as much as a tribunal...
Dave