Thankyou all for your very useful input on distance learning support. 
I'll try to summarise replies for the list:
My question was:
What is your  definition of "distance learning".
Do you extend the service to p.t. students who, for instance?:
   *  live a certain distance from the university (eg outside 30 mile
     radius)
   * are only timetabled to visit the campus a certain number of times
     per term

Definitions:
"Distance learners are those who separated by distance or by available 
time from the institution at which they are registered for the course" 
(Sconul Briefing papre 2001)
"Distance users are those separated from the University by geographic 
location, time, physical location, and impairment"
There is also the useful CHEST agreements definition at

http://www.eduserv.org.uk/chest/user-access.html.
for an understandably more limited definition.

Present practice falls into 3 groups. 
1. Distance Learning services only offered to students on distance learning courses (8 respondents)
2. Distance Learning services offered to students based on set of criteria which includes factors such as number of times students are timetabled to be on campus per week or per term. ( 3 respondents) To take an example:

    * students on designated distance learning programmes
    * students on programmes requiring occasional attendance on-campus
      (no more than two occasions per semester)
    * students on study placements of at leat 10 weeks, integral to the
      course
    * off-campus research students
    * lifelong learning/learn through work students
    * e-learning students
    * Home study students
    * students with individual circumastances which may prevent attendance

So in group 2, service provision is based not only on the programme but 
also on the user.

3. Distance Learning services either offered to all part-time students, 
or in some cases, to all students if they need the service. (6 respondents)
In the latter case a distance learner is " any students who wishes to 
use the service at a distance" and so takes in full-time students who 
may have conflicting responsibilities outside the university or have to 
undertake a long-distance daily commute etc.
Students have to register to use the service.

Services offered: (based on limited amount of info as this was not part 
of the original question)
Postal loans - in some cases postage of books to student paid by 
library, student has to pay return postage. Restriction on number of 
books sometimes applies. In other cases postage charged for books sent 
to students
Postal photocopy service. In some cases restrictions on numbers and/or 
level. Charges range from no charge,10p per page, £2 per item (postage 
sometimes included)
Postal interlibrary loan service. In some cases restrictions on numbers
Renew books by phone
Subject enquiries
Study skills resources
Help with access to other libraries

Thankyou so much to everyone who replied.  This has provided us with a 
great deal of useful information as a starting point to review the 
services we offer at Coventry  We do need to do more research, 
especially in relation to charges, if we are to think about widening the 
service to all students who have a need.
Best wishes
Stephanie Silvester
Head of Academic Support
Lanchester Library
Coventry University
Tel: 024 7688 7543