just gone out to the car and as i started it the check is saying that oil level too high i've contacted the garage who said just leave it till monday will this cause any damage ?

look on the dipstick, it could be a few mm over the max (will be fine) it could be 3 litres too much, so go look

btw- too much oil will cause damage.

if there is too much in there then yes it can cause damage internally. it pressurises and breaks the seals but that is worst case. check dipstick etc and get it checked but after sorting that keep an eye on your oil level if your seals are damaged oil will escape and burn off so you will notice oil level lowering if so take it to garage because can cause more problems to pistons

Did you recently change/add oil ?
Is it parked on level ground ?

i would check the oil level first
could just be a faulty sensor reading