The PO has put 275 55 20 on my Vogue and he also did the spare which is now too big for the well and has a home made cover on it. On my P38's I know not to never mix tyre sizes, even for a short distance, but on the L322 is it possible for 100 km or so. 2008 TDV8 Vogue
1970 2 door
1970 2 door
SOLD
1971 2 door
2000 4.6 Vogue
2001 4.6 Vogue
1994 3.9 Vogue
1990 4.2 Vogue SE
1981 2 door
1980 2 door
1988 4.6 Vogue SE

I wouldn't.

You need to check on one of the online convertors - there are some sizes that have the same rolling radius, so would theoretically be OK, but I'd just change it - even if it's for a part worn one of the same size as the rest of my tyres

your speedo will read faster,

Thanks Alistair my problem though is to do with the widthe and diameter.
There has been plastics removed to get the spare in. 2008 TDV8 Vogue
1970 2 door
1970 2 door
SOLD
1971 2 door
2000 4.6 Vogue
2001 4.6 Vogue
1994 3.9 Vogue
1990 4.2 Vogue SE
1981 2 door
1980 2 door
1988 4.6 Vogue SE