We have the same problem as you - the top panel is rusting and is a complete eyesore - I googled "Maxol Monte Carlo 3000" and your query was first on the list!
I have a Maxol oven too which we have just repaired ourselves but thankfully it didn't need anything nothing too drastic fixed. Have you tried seaching for Caravan Brookers on Google? There are plenty on the web and they may be able to help.
guys, i have a monte carlo in my hymer also, and guess what...its gone rusty. ive removed mine, plastered it in paint stripper, rubbed it down and found a can of spray paint in halfords which is almost an exact match (mine was rover arun white)
the oven is very easy to dismantle (about 10 minutes) and looks as good as new now its back together.
hi Hymer Bob - thanks for the tip - I might buy the stripper and the paint and give it to my husband to keep him busy - it will be worth a try - if all else fails I'll tackle it myself! Hopefully the weather on this emerald isle will improve for next season and then I can show off my gleaming oven!
Just responding to this old post in case anyone else has the same pronlem.
The part that rusts is the vent panel above the oven, not actually part of the oven itself, but it is attached to it.
It can be removed easily and then needs to be stripped of paint, rubbed down to bare metal and repainted using an etching primer and a heat-resistant paint.
The ovens were popular in the late 1980's to early 1990's but the manufacturer appears to have disappeared, as do many caravan product suppliers!