You can try Hotel Palace Heights. Stayed there and it was fine for a very short stay:
http://www.tripadvisor.com/Hotel_Rev..._of_Delhi.html
I see it's now #9 of 355 hotels in Delhi (this would be due to the value for money). The hotel is right on Connaught Place. The rooms are small and 'modern' furnished. But no facilities like pool etc.
I don't think they would allow late checkout but prices are very reasonable.
Regards
lme ff