im afraid i have to agree with the last few replies, especially Jugs re the quality of work etc
unfortuantely it seems the garage is calling the shots and saying 'ball park' prices for the work etc and then just sitting back knowing they will get a big payment at the end of it
if the work involved was sump and head gasket id expect the cost to be around 500 from a garage and 2 days in there, christ, if i could get the head to a machineist myself i could do it all in an afternoon really. the parts themselves should only cost 100 ish then its labour ontop. as said, ask and make sure you get an itemised bill, otherwise you wont know how youve been fleeced, and dont just let the 'headgasket' and 'sump' be put on the bill, ask for the individual part costings, machining for the head and labour involved.
it did appear that you had alot of people asking where you were other trhan glasgow and then they could point you in the rigyht direction, you even had one person offer to take a detour to have a look on your drive for you...
i think this is a very hard learning experience for you im afraid, and hopefully you can get it resolved to the point that your car is both reliable and doesnt hurt your pocket too much