Ok, end of my saga for now. as I said I cancelled my first service yesterday with Sandicliffe MG, Loughborough beciuse they were going to try and charge me £336.00! and I booked with Drive Motor Retail MG, Leicester who carried out the first service today (briiliant that they could do it at such short notice) and they charged mer £ 182.86! with full itemised invoice showing all the parts used: oil filter etc. and they washed and did a mini valet and renewed the breakdown cover. So, brilliant - I would highly recommend them, no hassle, they texted me with an update on what was happening during the service and when it was ready. So, if Leicester or any of the other MG dealers they own are in your area I would use them, at that price it ias worth travelling for.
The only downside to all of this, is the jumping through hoops I've had to do - that really should not be necessary and something is seriously wrong when 2 dealers are £153.14 difference, the highest prcie was nearly double the lowest price! MG needs to sort it out