Carvery/roast dinner in Glasgow - on a Saturday

Title says basically what I want to know - I'm in the city with my partner on Saturday and she has her mind set on having some kind of roast Saturday for some reason, can anybody recommend anywhere in Glasgow that does a carvery or roast dinner type of meal on a Saturday evening? Keen to avoid all these big chain restaurants and would prefer something near the centre but don't care too much as long as it isn't a massive trek (I'll have my car but don't want to go too far) and is decent value for money.