Chris Barrie came to fame doing voices on Spitting Image so he is a very hard act to follow but Rob Grant does an acceptable job but his vocal range is less engaging
This is infinitely better than the TV series of the equivalent bits. I wish they'd had a far bigger budget back then and an hour per episode rather than half hour. A movie / series of movies is in order!
The small scale and limited budget is the joy of the original TV series. Given more time and money would only ruin it all and a movie would be absolutely terrible. We have everything we could possibly want with Red Dwarf, we don't need it ruined like Star Wars and other abused franchises.
What they could perhaps do, is get the original cast members back and adapt the books into audio plays. Throw in some of the original music and sound effects, and we get the best of both.