Hello Warren and welcome to the forum
The Parva is a good basic bike but the width if the tyres is not going to affect its weight carrying ability, that would be more governed by the strength of the wheels. It looks like they are 32 spoke rather than 34 or 36 but should be up to carrying you without problems.
As far as I can see its unavailable at both
Halfords and Cycle Republic (a sub division of Halfords) so maybe a model change or update is on the way. Their Subway is available which is very similar but fifty quid more. They also have the Apollo Transfer but I wouldn't recommend them as they are very poor quality.