i am getting a lift to skc with friends who live a good distance from me about 2 hrs but going with them saves me from driving 5 hrs on my own So need a safe place to meet and leave car without having to pay a fortune to park around J40  on M6 any ideas please?

British Rail stations are usually reasonable to park for the day.

thanks do they have a closing time as dont know what time likely to leave skc

You'd need to check, but I'd imagine it would be pretty late as trains run to well past midnight and start again early.

When I used to meet work colleagues to combine trips we all used hotel car parks for decent security.  Big chains tend to have plenty of space, good lighting when you get back to your car at night, toilets and coffee whilst you wait and (usually) no fees.  You can always phone reception and check - tell them you want to start and end your day with coffee and/or food and they'll be more obliging!

There is a website called "Off the Motorway" or "Near the Motorway" or some such.  Have a Google of the Junction and see what comes up :)