what about diesels?Have a look on RPI website, the reasons are explained in detail.
I have owned and maintained several LR V8's and have never used synthetic or semi synthetic oil and top class independants have also verified this.
i wouldnt run a morris minor full stopNever owned a diesel because I dont have a HGV licence!!
Would you run a Morris Minor on fully synthetic???
Just to add.. the shop would rather sell you 5 litres of synthetic at say £30 than 5 litres of multigrade mineral at £16..it's all about mark up